Sound
 Differentiate b/t Infrasound and Ultrasound
 Give a reallife example of each
 Infrasound
 sound of a frequency TOO LOW to be perceived by the human ear.
 Ex: elephants can perceive infrasonic sounds that humans cannot
 Ultrasound
 sound of a frequency TOO HIGH to be perceived by the human ear.
 Ex: dogs can perceive ultrasonic sounds that humans cannot
 sound of a frequency TOO LOW to be perceived by the human ear.
 Ex: elephants can perceive infrasonic sounds that humans cannot
 sound of a frequency TOO HIGH to be perceived by the human ear.
 Ex: dogs can perceive ultrasonic sounds that humans cannot
 Lenses & Mirrors
 Image Types
 Differentiate b/t Virtual and Real images wrt location of IMAGE & LIGHT SOURCE
 Image Types
 Differentiate b/t Virtual and Real images wrt location of IMAGE & LIGHT SOURCE
Virtual Images
 there is NO ACTUAL LIGHT emanating from or reaching the image
 Ex: The image formed is behind a plane mirror
Real Images

THERE IS ACTUAL LIGHT at the image
 ex: Image formed on your retina
Electricity
 Conductance
 Define wrt how they deal with ELECTRON FLOW:
 conductor
 resistor
 insulator
 semiconductor
 superconductor
 Define wrt how they deal with ELECTRON FLOW:
CONDUCTOR
 is a material that allows the flow of electrons through it relatively UNIMPEDED
RESISTOR
 is a material that tends to IMPEDE the flow of electrons.
 This being said, even the best conductors do exhibit some small degree of resistance to the flow of electrons
 superconductors being the possible exception
 and all resistors do conduct electrons to some small degree
 This being said, even the best conductors do exhibit some small degree of resistance to the flow of electrons
INSULATOR
 is a material with a very, very high resistivity.
 There is NO perfect ideal insulator that allows zero current flow under all conditions.
 However, materials like glass and Teflon allow negligible current flow up to extremely high voltages.
 There is NO perfect ideal insulator that allows zero current flow under all conditions.
SEMICONDUCTOR
 is a material thought to be right in the middle of an insulator and a conductor (in terms of conductivity vs. resistivity).
SUPERCONDUCTOR
 is a material that under very precise conditions is thought to exhibit zero resistance to electron flow
 Deriving Electric Field equations
 Force
 Force
 For gravity near earth, F=mg

For a constant elec. field:
 F=qE

For "real" gravity, F=Gmm/r^{2}^{}^{}
 For a pointcharge elec. field:

F=Kqq/r^{2}^{} (Coulomb's Law)

For a constant elec. field:
 F=qE
 For a pointcharge elec. field:
 F=Kqq/r^{2}^{} (Coulomb's Law)
 Lenses & Mirrors
 The 4 Lens/Mirror Rules
 The 4 Lens/Mirror Rules
(for singlelens systems only!)

Object distances, p, are always ___

Image distances, q, or focal point distances, f, are

___ if they are on the SAME SIDE as the observer

___if they are on opposite sides

 The observer and object are on the:
 same side for a _____
 on opposite sides for a ____
 Explain "PRI/NVU"
 Object distances, p, are always (+)
 Image distances, q, or focal point distances, f, are
 (+) if they are on the SAME SIDE as the observer
 () if they are on opposite sides
 The observer and object are on the:

same side for a mirror
 on opposite sides for a lens

PRI/NVU:
 "Positive, Real, Inverted"
 "Negative, Virtual, Upright"

ALWAYS STAY TOGETHER!!!!!!!!!
 if you know 1 trait, you know the other 2 by association
 (+) if they are on the SAME SIDE as the observer
 () if they are on opposite sides
 same side for a mirror
 on opposite sides for a lens
 "Positive, Real, Inverted"
 "Negative, Virtual, Upright"

ALWAYS STAY TOGETHER!!!!!!!!!
 if you know 1 trait, you know the other 2 by association
 Electricity
 Charge
 Charge is QUANTIZED, according to?
 (what numerical value)
 Charge
 Charge is QUANTIZED, according to?
 (what numerical value)
 Charge is QUANTIZED, according to?
 e^{ }= 1.6 x 10^{19} C
 Magnetism
 How do electric fields and magnetic fields relate to each other?
 How do electric fields and magnetic fields relate to each other?
 Changing electric fields create magnetic fields
 any movement, velocity, rotation, etc. of a charged particle causes a change in the electric field created by that charge
 thus, creates a magnetic field
 Changing magnetic fields create electric fields
 any movement, velocity, rotation, etc. of a charged particle causes a change in the electric field created by that charge
 thus, creates a magnetic field
 Machines
 Levers
 Formula=?
 Levers
 Formula=?
 F_{m}=mg (L_{1}/L_{2})
 L_{1}= lever arm for the MASS
 L_{2}= lever arm for the APPLIED FORCE
 L_{1}= lever arm for the MASS
 L_{2}= lever arm for the APPLIED FORCE
 Circuits
 Solving circuits using Ohm's Law
 What if I can't adding things together doesnt yield a Simple Circuit?
 Kirchoff's Rules!
 Describe them (2)
 Solving circuits using Ohm's Law
 What if I can't adding things together doesnt yield a Simple Circuit?
 Kirchoff's Rules!
 Describe them (2)
 Kirchoff's Rules!
 What if I can't adding things together doesnt yield a Simple Circuit?
 Apply Kirchoff's rules
 1st Rule:
 current INTO node=current OUT OF node
 2nd Rule:
 In any cyclical circuit, V=0
 the sum of the voltage drops across each resistor equals the total voltage of the battery
 1st Rule:
 current INTO node=current OUT OF node
 2nd Rule:
 In any cyclical circuit, V=0
 the sum of the voltage drops across each resistor equals the total voltage of the battery
 In any cyclical circuit, V=0
 Sound
 General Characteristics
 How is sound produced?
 What are its properties as a mechanical wave?
 General Characteristics
 How is sound produced?
 What are its properties as a mechanical wave?
 Sound is always created by a vibrating medium
 these vibrations propagate through liquids or solids, and generate pressure waves that propagate through GASES (such as air)
 As a mechanical wave, sound CANNOT propagate in a vacuum
 these vibrations propagate through liquids or solids, and generate pressure waves that propagate through GASES (such as air)
 Waves
 The Doppler Effect
 Describe the "Doppler Shift"
 Give the 2 formulas
 The Doppler Effect
 Describe the "Doppler Shift"
 Give the 2 formulas
 The Doppler "Shift"
 perceived by observer
 dependent on the relative velocity b/t the SOURCE & OBSERVER

Greater the relative velocity, greater the shift in frequency or wavelength

Δf / f_{s}= v / c

f_{s}= "source" frequency

Δλ/λ_{s}= v / c

λ_{s}= "source" wavelength
 perceived by observer
 dependent on the relative velocity b/t the SOURCE & OBSERVER
 Greater the relative velocity, greater the shift in frequency or wavelength
 f_{s}= "source" frequency
 λ_{s}= "source" wavelength
 Forms of Energy
 Kinetic Energy formula
 Kinetic Energy formula
 KE= ½mv^{2}
 Electric Fields
 Deriving Electric Field equations
 how do you get these kinds of equations?
 what do you need to remember to differentiate between?
 Deriving Electric Field equations
 how do you get these kinds of equations?
 what do you need to remember to differentiate between?
 Use conversions for equations you already know for GRAVITY
 Be sure to differentiate between:

CONSTANT Electric Fields
 are derived by comparison to gravity NEAR EARTH

POINTCHARGE Fields
 are derived by comparison to "actual" gravity, or gravity IN SPACE

CONSTANT Electric Fields
 are derived by comparison to gravity NEAR EARTH

POINTCHARGE Fields
 are derived by comparison to "actual" gravity, or gravity IN SPACE
 Waves
 Wave speed
 Formula
 Name the "3 Cardinal Wave Rules"
 Wave speed
 Formula
 Name the "3 Cardinal Wave Rules"
 Formula
 V=λf
 3 CARDINAL WAVE RULES:
 Wave speed (velocity) is determined BY THE MEDIUM
 Frequency NEVER changes when a wave moves from medium to medium
 Wavelength DOES change when a wave moves from medium to medium
 V=λf
 Lenses & Mirrors
 Give the 3 formulas we need to know:
 The one for mirrors
 ThinLens equation
 Magnification equation
 Wrt (+/) signs, what does a negative M indicate?
 Give the 3 formulas we need to know:
 The one for mirrors
 ThinLens equation
 Magnification equation
 Wrt (+/) signs, what does a negative M indicate?

f=½r (for mirrors only!)

1/p+1/q=1/f (Thin Lens equation. Good for mirrors also)
 M= q /p = h_{q}/h_{p}
 Negative M= inverted image
 Waves
 Superposition of waves

The Beat Frequency
 Occurs when?
 what do waves need to have very similar to e/o?
 Give equation
 f_{beat}=?
 Superposition of waves

The Beat Frequency
 Occurs when?
 what do waves need to have very similar to e/o?
 Give equation
 f_{beat}=?
 Occurs when?

The Beat Frequency
 Occurs when 2 waves with close to the same FREQUENCY interfere with e/o
f_{beat}= f_{1 } f_{2}
 Optical Power
 Describe OP for TwoLens Systems
 what are some examples of 2 lens systems?
 Give formulas for Magnification and Power
 Describe OP for TwoLens Systems
 what are some examples of 2 lens systems?
 Give formulas for Magnification and Power
 The image formed by the first lens BECOMES THE OBJECT for the second lens
 Ex: binoculars, telescopes, microscopes, etc.
 Magnification
 M=m_{1}m_{2}
 Power
 P=p_{1}+p_{2}
 Ex: binoculars, telescopes, microscopes, etc.
 M=m_{1}m_{2}
 P=p_{1}+p_{2}
 Sound
 Harmonics
 Why does a pipe open at BOTH ends give all harmonics, but a pipe open at one end and closed at the other only gives the odd harmonics?
 Harmonics
 Why does a pipe open at BOTH ends give all harmonics, but a pipe open at one end and closed at the other only gives the odd harmonics?
 For a pipe open at one end and closed at the other, the first harmonic features a node at one end and an antinode at the other.
 It is impossible to have a node at the open end of a pipe and impossible to have an antinode at the closed end of a pipe.
 These facts restrict the possible waveforms.
 The logical “next step,” if you will, to move to the next harmonic from the first one is to add a node—
 this is impossible, however, because it would require that there be nodes at both ends of the pipe.
 Thus, we skip this step and add one node and one antinode to get the third harmonic.
 this is impossible, however, because it would require that there be nodes at both ends of the pipe.
 Thus, we skip this step and add one node and one antinode to get the third harmonic.
 Electric Fields
 Deriving Elec Field equations
 PE_{elec}
 Deriving Elec Field equations
 PE_{elec}
 For gravity near earth, PE_{grav}=mgh (height measured against gravity)
 For a constant elec field:

PE_{elec}=qEd (distance measured against strength of elec. field)
 For "real" gravity, PE_{grav}=Gmm/r
 for a pointcharge elec field:

PE_{elec}=Kqq/r OR
 PE_{elec}=Kqq/r
 For a constant elec field:
 PE_{elec}=qEd (distance measured against strength of elec. field)
 for a pointcharge elec field:
 PE_{elec}=Kqq/r OR
 PE_{elec}=Kqq/r
Circuits
 Resistance
 How can "resistance" be conceptualized/compared to:
 ____in fluids or ____ between solids
 Give the Formula for resistance
 How is Resistance "Temperature Dependent?"
 The wires b/t any 2 elements in a circuit are assumed to be PERFECT _____S
 wherein resistance=___
 All resistance occurs where?
 How can "resistance" be conceptualized/compared to:
Resistance can be conceptualized as the equivalent of:
 DRAG in fluids or FRICTION between solids
R=ρL/A
 ρ=resistivity
 L=length
 A=crosssectional area
Temperature Dependence
 Starting around room temp, an increase in temperature results in:
 a linear increase in resistivity
 Changing temp is the ONLY WAY you can change resistance in a circuit without replacing the resistor
The wires b/t any 2 elements in a circuit are assumed to be PERFECT CONDUCTORS!
 resistance=zero
 all resistance occurs at the resistors
Waves
 Types of Waves

Electromagnetic (EM) Waves
 What kind of medium is req'd for these waves?
 EM waves are capable of propagating in WHAT?
 Can they transfer energy, momentum, or both?
 Are they transverse or longitudinal?
 Give examples of EM waves

Electromagnetic (EM) Waves

NO medium required!
 Capable of propagating in a vacuum
 Can transfer BOTH energy & momentum
are TRANSVERSE ONLY
Ex: visible light, microwaves, radio waves
 Wave Speed
 Wave velocity (v) in various mediums
 Describe velocity of a wave on a string
 Here, what are its elastic & intertial properties?
 How does increasing these properties affect V?
 Wave velocity (v) in various mediums
 Describe velocity of a wave on a string
 Here, what are its elastic & intertial properties?
 How does increasing these properties affect V?
 Describe velocity of a wave on a string
 The elastic property (that provides the restoring force in a string)

is the string's TENSION
 Increased tension always increases velocity.
 The inertial property
 is mass per unit length, the “linear mass density”
 μ: v = √(T/μ).
 A thicker string (increased mass per length) always decreases velocity (provided the tension stays the same)
 is the string's TENSION
 Increased tension always increases velocity.
 is mass per unit length, the “linear mass density”
 μ: v = √(T/μ).
 A thicker string (increased mass per length) always decreases velocity (provided the tension stays the same)
 Waves
 Superposition of waves
 Differentiate b/t areas of constructive & descructive interference
 Superposition of waves
 Differentiate b/t areas of constructive & descructive interference
 Constructive Interference
 regions where the amplitudes of superimposed waves ADD TO each other

INCREASES amplitude
 Destructive Interference
 regions where the amplitudes of superimposed waves SUBTRACT FROM each other

DECREASES amplitude
 regions where the amplitudes of superimposed waves ADD TO each other
 INCREASES amplitude
 regions where the amplitudes of superimposed waves SUBTRACT FROM each other
 DECREASES amplitude
 Machines
 What do machines do? What do they never do?
 What do machines do? What do they never do?
 They reduce the amount of forces necessary to perform a given amount of work
 They NEVER reduce or change the amount of work
 Electromagnetic Spectrum
 Describe Visible Light
 λ=?
 Describe RED light (3)
 Describe Violet light (3)
 Mnemonic=?
 Describe Visible Light
 λ=?
 Describe RED light (3)
 Describe Violet light (3)
 Mnemonic=?
 390700nm

RED LIGHT

lowest energy

lowest frequency

longest λ

VIOLET LIGHT

highest energy

highest frequency

shortest λ
 Mnemonic:
 ROYGBIV
 lowest energy
 lowest frequency
 longest λ
 highest energy
 highest frequency
 shortest λ
 ROYGBIV
 Machines
 Ramps
 Formula
 What does a "5 meter long" ramp or a "5 meter ramp" imply?
 Ramps
 Formula
 What does a "5 meter long" ramp or a "5 meter ramp" imply?
 Formula

F_{m}=mg (h/d)
 h=height of ramp
 d=distance along its hypotenuse
 F_{m}=force necessary to do the work with the machine
 "5 meter ramp" or "5 meters long"
 implies that the hypotenuse of the ramp is 5m
 h=height of ramp
 d=distance along its hypotenuse
 F_{m}=force necessary to do the work with the machine
 implies that the hypotenuse of the ramp is 5m
 Circuits
 Ohm's Law
 Formula
 What is a common error when manipulating equations using Ohm's Law?
 Ohm's Law
 Formula
 What is a common error when manipulating equations using Ohm's Law?
 Formula
 V=IR
 Common error:
 it CANNOT be said that if voltage increases and current remains constant that resistance will INCREASE
 Resistance is a permanent quality of the resistor itself
 The only way to change resistance is to:
 physically replace resistors with resistors that have different Ohm's ratings, or
 change the temperature of the resistor
 V=IR
 it CANNOT be said that if voltage increases and current remains constant that resistance will INCREASE
 Resistance is a permanent quality of the resistor itself
 The only way to change resistance is to:
 physically replace resistors with resistors that have different Ohm's ratings, or
 change the temperature of the resistor
 The Law of Conservation of Energy

Energy in a/n ____ system is always ____
 Describe this Law

Energy in a/n ____ system is always ____
 Describe this Law

Energy in an ISOLATED system is always CONSERVED
 Energies (KE, PE, Heat Energy, etc.) are frequently transferred back and forth, but NEVER LOST
 Energies (KE, PE, Heat Energy, etc.) are frequently transferred back and forth, but NEVER LOST
 Electric Fields
 Comparing Elec. Field equations to Gravity
 What (in gravity equations) equates to what (in elec. field equations)?
 Comparing Elec. Field equations to Gravity
 What (in gravity equations) equates to what (in elec. field equations)?
Example to start you off:
g (stength of grav. field) = E (strength of electric field)

g (stength of grav. field)
 =E (strength of electric field)

G (constant)

K (constant)

h (distance)
 =r or d

m (mass)
 =q (charge)

F (force)
 =F (same in both)

gh (PE_{grav})
 =V (voltage, PE_{electrical})
 =E (strength of electric field)
 K (constant)
 =r or d
 =q (charge)
 =F (same in both)
 =V (voltage, PE_{electrical})
 Optical Power
 Formula (for singlelens systems)
 Formula (for singlelens systems)
 P=1/f
Electric Fields
 Electric Dipoles

"a dipole is a _______ of positive & negative charges of ____ _______"
 What happens when a dipole is exposed to an electric field?
 What if the dipole DOESNT do the above thing when exposed to B?
 What does it HAVE, then?

a dipole is a separation of positive & negative charges of EQUAL magnitude
When a dipole is exposed to an elec. field, it tends to align itself with that field

a dipole that is NOT aligned with the elec. field has PE
 alignment with the field is a lower energy state than alignment AGAINST the field
 Electricity
 Charge
 Explain "Conservation of Charge"
 Charge
 Explain "Conservation of Charge"
 The Universe always has a ZERO net charge
 Charge is created by separation
 If you separate one electron from a neutral atom, you have created:
 one independent unit of negative charge (the electron)
 and simultaneously created one independent unit of positive charge (the cation)
 If you separate one electron from a neutral atom, you have created:
 one independent unit of negative charge (the electron)
 and simultaneously created one independent unit of positive charge (the cation)
Electric Fields

Electric Field Lines

Always drawn with their ____s at the POSITIVE charge

_____ LINES=STRONGER FIELD
 Field Lines best approximate "____ flow"
 What is the opposite of this kind of flow?

 Always drawn with their tails at the positive charge
 Pointing AWAY FROM, or
 Pointing TOWARDS the negative charge
 CLOSER LINES=STRONGER FIELD
 Field Lines best approximate Current Flow
 Current flows from positive to negative concentrations
 Pointing AWAY FROM, or
 Pointing TOWARDS the negative charge
 Current flows from positive to negative concentrations
ELECTRON Flow is the opposite (neg.⇒pos.)
 Waves
 Types of Waves
 compare Transverse vs. Longitudinal waves
 Types of Waves
 compare Transverse vs. Longitudinal waves
 Transverse waves
 displace the medium perpendicular to their direction of travel
 ex: EM waves, waves on a string
 Longitudinal waves
 displace the medium parallel to their direction of travel
 ex: sound waves, pwave earthquakes
 displace the medium perpendicular to their direction of travel
 ex: EM waves, waves on a string
 displace the medium parallel to their direction of travel
 ex: sound waves, pwave earthquakes
 Wave Speed
 Wave Velocity in various mediums
 velocity of sound waves in a SOLID

what are the elastic & inertial properties?
 How do these sound waves differ than the ones going through a gas?
 Wave Velocity in various mediums
 velocity of sound waves in a SOLID
 what are the elastic & inertial properties?
 How do these sound waves differ than the ones going through a gas?
 velocity of sound waves in a SOLID
 Elastic property: "Bulk Modulus" (B)
 Inertial property: Density, ρ
 Although the densities of solids are typically thousands of times higher than the densities of gases...
 the elastic moduli are even increased by an even LARGER factor!!
 This property causes solids to “spring back” extremely quickly following deformation.
 Sound (compression) waves in solids are therefore TYPICALLY MUCH FASTER THAN SOUND WAVES IN GASES .
 Power
 Formulas
 Think of power in THIS ORDER (4)
 Units=?
 Formulas
 Think of power in THIS ORDER (4)
 Units=?
 P=ΔE/t
 P=W/t
 P=Fscosθ

P_{i}=Fvcosθ
 gives "instantaneous power"
 should only be used when asked for specifically

Units: Watts
 J/s
 gives "instantaneous power"
 should only be used when asked for specifically
 J/s
 Wave Characteristics
 Describe
 wavelength
 period
 velocity
 frequency
 intensity
 phase
 Describe
 wavelength
 period
 velocity
 frequency
 intensity
 phase
 Wavelength (units = meters)
 distance between two adjacent:
 crests (a.k.a., peaks, maxima),
 troughs (a.k.a., valleys, minima).
 Period and frequency are ALWAYS INVERSES OF EACH OTHER!!
 Velocity

how fast the wave moves in space (in m/s).
 given by v = fλ.
 Amplitude
 the “distance” between:
 the equilibrium point and a crest, or between the equilibrium point and a trough.
 Intensity is
 a measure of power per unit area.
 Waves have power because they transport energy from one point to another in a given amount of time.
 Intensity is proportional to the square of the amplitude and the square of the frequency.
 Phase
 is a relative measure of how closely two waves (typically with the same frequency) are oriented to one another in space,
 typically expressed in radians or degrees.
 Two waves that are “in phase” should cross the xaxis at the same point, but may have different amplitudes
 distance between two adjacent:
 crests (a.k.a., peaks, maxima),
 troughs (a.k.a., valleys, minima).
 how fast the wave moves in space (in m/s).
 given by v = fλ.
 the “distance” between:
 the equilibrium point and a crest, or between the equilibrium point and a trough.
 a measure of power per unit area.
 Waves have power because they transport energy from one point to another in a given amount of time.
 is a relative measure of how closely two waves (typically with the same frequency) are oriented to one another in space,
 typically expressed in radians or degrees.
 Two waves that are “in phase” should cross the xaxis at the same point, but may have different amplitudes
 Light
 Describe how Young's DoubleSlit experiment was physically SET UP

What needed to happen for his experiment to work?
 Describe how Young's DoubleSlit experiment was physically SET UP
 What needed to happen for his experiment to work?
 Young shone a monochromatic light through a screen with a single slit in it.
 The purpose of this slit was to create coherent wavefronts
 Behind the first screen he placed a second screen with two narrow, parallel slits.
 These created the diffraction pattern.
 Finally, behind the second screen he placed a third screen.
 Light traveled through the first two screens and formed alternating pattern of LIGHT and DARK bands on the third screen.
 The purpose of this slit was to create coherent wavefronts
 These created the diffraction pattern.
For the experiment to work, the light traveling through each of the 2 slits in the middle screen must be coherent and have the SAME FREQUENCY & POLARIZATION
 Electric Fields
 Think of a "Field" as...?
 Think of a "Field" as...?

FIELD= an invisible influence capable of exerting a FORCE on a:
 mass, or
 charge
 mass, or
 charge
 Think of the formulas for WORK in this order (2)
 If ____ changed, think WORK!
 If ____ changed, think WORK!
 W=Δ Energy
 W=Fdcosθ
 If ENERGY changed, think WORK!
 Lenses & Mirrors
 NearSighted vs FarSighted
 describe
 Where is the image in relation to the location of the retina?
 NearSighted vs FarSighted
 describe
 Where is the image in relation to the location of the retina?
 Nearsighted (myopia)
 able to focus clearly on CLOSE objects, but not on distant ones
 The image is IN FRONT OF the retina
 Farsighted (hypertropia)
 able to focus clearly on DISTANT objects, but not on close ones
 The image is BEHIND the retina
 able to focus clearly on CLOSE objects, but not on distant ones
 The image is IN FRONT OF the retina
 able to focus clearly on DISTANT objects, but not on close ones
 The image is BEHIND the retina
 Light
 Dual nature
 Define particle & wave models for light
 What specific experiment/effect supports each model?
 Dual nature
 Define particle & wave models for light
 What specific experiment/effect supports each model?
 Define particle & wave models for light
How are these two models reconciled?
The Wave Model of light
supposes that light is a wave

Young’s Double Slit Experiment provides support for this model
 because only waves would show the diffraction and interference patterns necessary to create the characteristic light and dark bands
The Particle Model of light
supposes that light is a particle

The photoelectric effect is the major support for this model.
 Says that electrons are ejected from a material when light of sufficiently high frequency is used—
 but NOT UNTIL a threshold frequency is reached.
 Says that electrons are ejected from a material when light of sufficiently high frequency is used—
The two are reconciled by:
QUANTUM MECHANICS!
photons are described by “wave functions” which sometimes act as
 macroscopic waves, and sometimes as
 macroscopic particles
 Waves
 In order for 2 waves to be "in phase" with each other:
 What 3 characteristics must they share?
 Which of these 3 is MOST IMPORTANT?

What do the 2 waves need to share in order to have this characteristic?
 In order for 2 waves to be "in phase" with each other:
 What 3 characteristics must they share?
 Which of these 3 is MOST IMPORTANT?
 What do the 2 waves need to share in order to have this characteristic?
 Which of these 3 is MOST IMPORTANT?
 What 3 characteristics must they share?
 In order to be 100% in phase, two waves would have to have the same:
1) Frequency,
2) Wavelength
and most importantly
3) TIMING OF MAXIMA/MINIMA
 which could be done if they share the same time/place of origin)
 Light
 Energy of a Photon
 Formula
 Energy of a Photon
 Formula

E=hf
 h=Plack's constant (given)
 h=Plack's constant (given)
Waves
 Types of Waves
 What are MECHANICAL Waves?
 2 traits:
 What do they require to propagate?
 Do they transfer energy, momentum, or both?
 Are they Transverse or Longitudinal or Both?
 2 traits:
 What are MECHANICAL Waves?

REQUIRE A MEDIUM to propagate
 Transfer ENERGY ONLY!!! (not momentum)
Can be BOTH transverse & longitudinal
 Transverse
 transverse mechanical waves require a fairly STIFF MEDIUM in order to propagate
 ∴ cannot propagate in liquids or gases
 ex: strings on a musical instrument
 transverse mechanical waves require a fairly STIFF MEDIUM in order to propagate
 Longitudinal
 ex: sound waves
 Define Chemical Energy
 The energy contained within chemical bonds
 Or the energy stored/released due to the separation and/or flow of ELECTRONS
 i.e. a battery
 i.e. a battery
 Electric Fields
 What are 2 additional ways to think of "voltage?"
 What are 2 additional ways to think of "voltage?"
1.) Voltage =Potential Energy DIVIDED by charge or mass
2.) Voltage= whatever "thing" you can MULTIPLY by mass or charge to get Potential Energy
 Examples:
 gh*m=mgh=PE_{gravitational}
 Ed*q=PE_{electrical}=V*q
Electromagnetic Spectrum
 List (in order) each class of the EM spectrum and their relative ENERGIES (10^{x})
 Hint:
 Remember My Interest Varies Under
Xternal Groups

Radio waves
 10^{3}

Microwaves
 10^{2}

Infrared waves
 105

Visible Light
 10^{6}

Ultraviolet light
 10^{8}

Xrays
 10^{10}

Gamma Rays
 10^{12}
 10^{3}
 10^{2}
 105
 10^{6}
 10^{8}
 10^{10}
 10^{12}
Waves
 Intensity
 The Decibel (dB) System
 Define
 How is it similar to & differ from the Richter scale (for earthquakes)
 The Decibel (dB) System
is a rating system for the intensity of sound within the range of human hearing
Both it and the Richter scale use logarithmic scales
 Difference:
In short:
10x increase on Richter Scale = 1 unit increase
10x increase on dB scale=10 unit increase
10x increase in earthquake intensity=1.0 unit increase on Richter scale
10x increase in sound intensity=10.0 unit increase on dB scale
 a sound 10x more intense is 10dB higher
 a sound 100x more intense is 20 dB higher
 a sound 1000x more intense is 30 dB higher
 Circuits
 Solving Circuits using Ohm's Law
 How to add in series/parallel:
 Resistors
 Capacitors
 Batteries
 Solving Circuits using Ohm's Law
 How to add in series/parallel:
 Resistors
 Capacitors
 Batteries
 How to add in series/parallel:
 Resistors
 in series:
 add directly
 in parallel:
 add the inverses
 take the inverse of that sum
 Capacitors (opposite of solving for resistors)
 in series:

add the inverses

take the inverse of that sum
 In parallel:
 add directly
 Batteries
 in series:
 add directly
 in parallel:

TOTAL voltage= the HIGHEST voltage of any one of the batteries in parallel
 in series:
 add directly
 in parallel:
 add the inverses
 take the inverse of that sum
 in series:

add the inverses

take the inverse of that sum

 In parallel:
 add directly
 in series:
 add directly
 in parallel:
 TOTAL voltage= the HIGHEST voltage of any one of the batteries in parallel
 Waves
 Types of Waves
 List the ones we're supposed to know
 Types of Waves
 List the ones we're supposed to know
 Transverse vs Longitudinal
 EM Waves
 Mechanical Waves
Sound
 Sound Resonance
 Explain how objects have "natural frequencies" and what a "harmonic" is
All objects have one or more natural frequencies at which they will vibrate when disturbed.
 Some objects produce a random array of different vibrational frequencies.
 Other objects (i.e., musical instruments) vibrate at nonrandom natural frequencies
 which are integer multiples of a number (e.g. 200Hz, 400Hz, 600Hz, 800Hz).
 These orderly frequencies are called "HARMONICS"
 W=Δ Energy
 When you see the following 6 situations, think WORK!
 Which of these 6 is the most common example of work you'll see?

What's an important caveat to remember about energy transfer in a system?
 When you see the following 6 situations, think WORK!
 Which of these 6 is the most common example of work you'll see?
 What's an important caveat to remember about energy transfer in a system?
 Change in VELOCITY
 change in KE=work!
 most common example!
 Change in HEIGHT
 change in PE_{grav} = work
 Change in POSITION (of masses/planets/etc.) IN SPACE

change in PE_{grav} = work

COMPRESSION of a spring
 change in PE_{elastic = work}

FRICTION
 change in internal energy=work

AIR RESISTANCE

change in internal energy=work
 change in KE=work!
 most common example!
 change in PE_{grav} = work

change in PE_{grav} = work
 change in PE_{elastic = work}
 change in internal energy=work

change in internal energy=work
CAVEAT:
Energy transfer in a system could be due to Heat Transfer as well!!

nonconservative forces dissipate some heath energy
 this leaves LESS energy available to do work
 Use of word "heat" refers to an increase in the internal energy of the molecules, NOT "heat transfer" ('Q' from the first law of Thermodynamics).
Sound
 Drawing Harmonics:
For a single vibrating guitar string of the same length
 the 1^{st} harmonic is only __ of a __
 the 2^{nd} harmonic is exactly __ __
 the 3^{rd} harmonic is __ __
The harmonics shown below are all for a single vibrating guitar string of the same length
 Notice:
 the 1st harmonic is only ½ of a λ
 the 2nd harmonic is EXACTLY 1 λ
 the 3rd harmonic is 1½ λ
Waves
 Define "INTENSITY"
 Give Units
 How does intensity relate to waves?
 What is intensity directly proportional to in:
 SOUND (aka "mechanical") waves
 LIGHT waves
Intensity= POWER per unit area
Units: Waves/m^{2}
 Waves often have power (often called "sound power")
 because they transfer energy from one location to another w/in a specified time
 (aka, energy flux)
 because they transfer energy from one location to another w/in a specified time
In sound or mechanical waves, Intensity is DIRECTLY PROPORTIONAL TO:
 AMPLITUDE ^{2}
 FREQUENCY^{2 }
^{}In LIGHT waves, intensity is directly proportional to:
 AMPLITUDE^{2}
But NOT (!!) FREQUENCY^{2}
 W=Fdcosθ
 Think of this definition of work 1st/2nd?
 Any time a ___ has been applied across a _____, WORK has been done
 Units=____, which is equivalent to? (2)
 Think of this definition of work 1st/2nd?
 Any time a ___ has been applied across a _____, WORK has been done
 Units=____, which is equivalent to? (2)
Think of this definition second
(First should be W= Δ in energy)
 Any time a force is applied across a displacement, work has been done
Units: Joules, aka:
 N*m
 kg*m^{2} /s^{2}
Waves
 Intensity
 Why do sound waves create spherical shapes when traveling from their point of origin?

MAGNITUDE OF INTENSITY _____es according to ___ of the growing sphere created by sound waves
 Why? (Has to do with how Intensity is measured; waves/m^{2})
Many waves (such as sound) travel outward from their origin in ALL directions SIMULTANEOUSLY
...which creates a wave front in the
shape of a growing sphere
Magnitude of Intensity DECREASES according to AREA of the growing sphere
 b/c intensity is measured per square meter
INcreasing m^{2} leads to a DEcrease in Intensity (ODI)
 A=4πr^{2}
 Circuits
 Voltage
 Think of "voltage" as...?
 What's another "intuitive way" of thinking about voltage?
 2 formulas
 Voltage
 Think of "voltage" as...?
 What's another "intuitive way" of thinking about voltage?
 2 formulas
Voltage=the amount of PE a system is capable of storing per unit charge
V=PE_{sys}/q
 Another way:
 Voltage=the amount of work necessary to move a charge against the electric field
 moving a longer distance requires more work (voltage increases with distance)
 Voltage=the amount of work necessary to move a charge against the electric field
Formulas:
 V=Ed
 V=Kq/r
Circuits
 Capacitors
 The Dialectric
 Describe what it is and what it does

INCREASING Dialectric=_____ing Capacitance
 Which allows for...?
 The dialectric must always be a ______or
 The Dialectric
The "dialectric" is the
substance BETWEEN the two plates
 ALL capacitors have a dialectric, even if it is just air
 Other dialectrics=gel, composites, etc.
 once inserted, some energy stored in the capacitor is used to align the polar molecules in the dialectric (ie, dipoles) with the field between the plates
 Increasing the strength of the dialectric increases the capacitance
 allowing more charge and energy to be stored
INCREASING dialectric=INCREASING capacitance
 The dialectric must always be an INSULATOR.
 Waves
 The Doppler Effect
 Remember these 3 key points:
 "v" is _____ velocity
 "c" is the ____ of the ___
 Does the answer of the equation usually give us that answer we need?
 The Doppler Effect
 Remember these 3 key points:
 "v" is _____ velocity
 "c" is the ____ of the ___
 Does the answer of the equation usually give us that answer we need?
 Remember these 3 key points:
 The variable v is RELATIVE velocity

NOT the velocity of either object
 The variable c is the speed of the wave
 3 x 10^{8} m/s for light
 340 m/s for sound
 The answer is of the equation isCHANGE IN λ
 which is often NOT what they're asking for!!
 NOT the velocity of either object
 3 x 10^{8} m/s for light
 340 m/s for sound
 which is often NOT what they're asking for!!
This value must be added or subtracted from the initial value in order to get the ACTUAL value due to the doppler effect
 Add to the frequency (subtract from the λ) if the relative motion is towards each other
 Add to the λ (subtract from the frequency) if the relative motion is away from each other
 Light
 Young's Double Slit experiment
 Equation
 Define diffraction
 Young's Double Slit experiment
 Equation
 Define diffraction

x=λL/ d
 x=distance b/t fringes
 λ=wavelength of light used
 d=distance b/t the two slits
 L=distance b/t doubleslit and final screen
 Diffraction
 is the tendency of light to spread out as it goes:
 around a corner, or
 through a slit

equally as important as constructive & destructive interference in Young's experiment
 without it, Young's characteristic interference patterns wouldnt be formed
 x=distance b/t fringes
 λ=wavelength of light used
 d=distance b/t the two slits
 L=distance b/t doubleslit and final screen
 is the tendency of light to spread out as it goes:
 around a corner, or
 through a slit

equally as important as constructive & destructive interference in Young's experiment
 without it, Young's characteristic interference patterns wouldnt be formed
 Sound
 Harmonics
 Formulas (2)
 Differentiate b/t when to use each
 show their rearranged forms
 Harmonics
 Formulas (2)
 Differentiate b/t when to use each
 show their rearranged forms
 Formulas (2)

L=nλ/ 2
 For string or pipe with matching ends
 Both nodes or both antinodes
 Gives all nodes
 n=1,2,3...
 Rearranged: λ=2L/ n
 L=nλ/ 4

For one node and one antinode
 Pipe open at one end ONLY
 Gives only the ODD harmonics!

n=1,3,5...
 Rearranged: λ=4L/ n
 For string or pipe with matching ends
 Both nodes or both antinodes
 Gives all nodes
 n=1,2,3...
 Rearranged: λ=2L/ n

For one node and one antinode
 Pipe open at one end ONLY
 Gives only the ODD harmonics!
 n=1,3,5...
 Rearranged: λ=4L/ n
 Circuits
 Current flows ____ wrt to electron flow?
 Current formula
 Current flows from __ to __
 Electrons flow from __ to __
 Current flows ____ wrt to electron flow?
 Current formula
 Current flows from __ to __
 Electrons flow from __ to __
 Current flows opposite to the direction of electron flow
 I=Δq/Δt
 Current flows from positive to negative
 Electrons flow from negative to positive
 I=Δq/Δt
 Snell's Law
 Total Internal Reflection
 What is the "Critical Angle?"
 What happens if it is exceeded?
 Total Internal Reflection
 What is the "Critical Angle?"
 What happens if it is exceeded?
 For waves passing from higher index mediums into lower index mediums, the critical angle is the angle of incidence for which the angle of refraction will be 90°.
 If this angle is exceeded, refraction ceases and all waves are reflected back into the more dense medium (Total Internal Reflection)
 Torque & Lever Arms
 Fulcrums & Boards on Strings
 are simply ___ problems
 how do you solve?
 Fulcrums & Boards on Strings
 are simply ___ problems
 how do you solve?
 are simply ___ problems
 are simply equlibrium problems
 To Solve:
 set Tclockwise=Tcounterclockwise
 Include ALL torques
 including T created by mass of the board
 Force due to mass of the board will act as center of mass
 will always be the exact linear center of a uniform board
 Dont forget to set torques equal to e/o, NOT FORCES!!!
 units: N*m
 Forces or tensions located exactly at center of rotation do NOT CREATE A TORQUE!! (ignore)

since r=0
 set Tclockwise=Tcounterclockwise
 Include ALL torques
 including T created by mass of the board
 Force due to mass of the board will act as center of mass
 will always be the exact linear center of a uniform board
 Dont forget to set torques equal to e/o, NOT FORCES!!!
 units: N*m
 Forces or tensions located exactly at center of rotation do NOT CREATE A TORQUE!! (ignore)
 since r=0
 Include ALL torques
 The WorkEnergy Theorem
 Describe
 Formula
 Best to just think of it as...?
 Describe
 Formula
 Best to just think of it as...?
 If a net force does work on a rigid object, the work done on that object is equal to the change in the KE of the object
 W= KE_{final } KE_{initial}

Focus on ΔE
 if you think of it this way, there is no need to use the WorkEnergy Theorem
 if you think of it this way, there is no need to use the WorkEnergy Theorem

Forms of Energy

Gravitational PE formula
Forms of Energy

Gravitational PE formula
 PE_{g}= Gmm/r
 Magnetism
 Give 4 examples of things that involve moving charges, and thus create a magnetic field
 Give 4 examples of things that involve moving charges, and thus create a magnetic field
 Nuclei with an odd atomic # or mass #
 they exhibit nuclear spin
 Electrons
 because they orbit and spin
 Current
 because it IS moving electrons
 Bar Magnets
 usually made of nickel, iron, or other alloy
 Normally, electrons in a metal are approximately split between spin states
 In bar magnets, though, they are partially aligned, creating a net magnetic field
 they exhibit nuclear spin
 because they orbit and spin
 because it IS moving electrons
 usually made of nickel, iron, or other alloy
 Normally, electrons in a metal are approximately split between spin states
 In bar magnets, though, they are partially aligned, creating a net magnetic field
Electric Fields

Equipotential Lines
 How are they draw in comparison to FIELD LINES?
 What do Equipotential lines represent?
 Are drawn perpendicular to field lines
 Represent areas of equal voltage (i.e. electrical potential)
 Electricity
 Charge
 What is a BIG MISCONCEPTION about Charge?
 Charge
 What is a BIG MISCONCEPTION about Charge?
 Thinking of positive charges as tiny little "things" with an inherent charge
 similar to electrons, except positive
 This is (essentially) a positron

Protons also fit this concept

FORGET ABOUT POSITRONS & PROTONS when it comes to:

circuits, electricity, current, etc.
 Positive charge is ALWAYS:

a LACK OF ELECTRONS (relative to being neutral)
 similar to electrons, except positive
 This is (essentially) a positron
 Protons also fit this concept
 circuits, electricity, current, etc.
 a LACK OF ELECTRONS (relative to being neutral)
 Circuits
 Ohm's Law across a resistor states that...?
 Ohm's Law across a resistor states that...?

Voltage drop across THAT resistor=current through THAT resistor X resistance of THAT resistor
 Sound
 Harmonics
 Characteristics (3)
 Frequency of any harmonic is equal to..?
 For oscillators with matching ends, the λ of the 2nd harmonic equals..?
 Harmonics
 Characteristics (3)
 Frequency of any harmonic is equal to..?
 For oscillators with matching ends, the λ of the 2nd harmonic equals..?
 The frequency of the first harmonic is called the “fundamental frequency.”
 Each additional harmonic has its own unique frequency and wavelength.
 Each harmonic always has one more node, and one more antinode, than the previous harmonic.
The frequency of any harmonic is equal to:
n*fundamental frequency
 (e.g., if the first harmonic is exactly 200 Hz, the 2nd is 400 Hz, the 3rd is 600 Hz, etc.)
For oscillators with matching ends, the wavelength of the second harmonic equals:
the LENGTH of the string or pipe (λ= L)
 Electric Fields
 Deriving Elec Field equations
 Voltage
 Deriving Elec Field equations
 Voltage
 For gravity near earth, V=gh
 For a constant elec field:

V=Ed (d measured against strength of elec field, E)
 For "real" gravity, V=Gm/r
 for a pointcharge elec field:
 V=Kq/r
 For a constant elec field:
 V=Ed (d measured against strength of elec field, E)
 for a pointcharge elec field:
 V=Kq/r
 Work
 The 1st Law of Thermodyamics
 Describe
 Formula
 The 1st Law of Thermodyamics
 Describe
 Formula
 Energy change is not ALWAYS due to work
 some energy is lost to/dissipated as heat
 Work + Heat are the ONLY TWO WAYS energy can be transferred in/out of a system
 ΔE= W+Q
 Work=energy transfer due to a force
 Heath=energy transfer via energy flow from Hot⇒Cold
 some energy is lost to/dissipated as heat
 Work=energy transfer due to a force
 Heath=energy transfer via energy flow from Hot⇒Cold
 Waves
 Intensity
 Define "Attenuation"
 what 2 things cause it in nondispersive mediums (like EM waves in a vacuum or ideal strings)
 Intensity
 Define "Attenuation"
 what 2 things cause it in nondispersive mediums (like EM waves in a vacuum or ideal strings)
 Define "Attenuation"
 the gradual loss of intensity as a wave passes through a medium
 In nondispersive mediums, this is due to scattering (i.e. reflection) of some waves and absorption of wave energy
Sound
 Harmonics
 What are Overtones?
 How do they relate to harmonics?
 What are Overtones?
 The terms “1st overtone,” “2nd overtone,” etc., are sometimes used.
 The 1st overtone is NOT the same as the 1st harmonic!!!!
 The first harmonic is called
 the fundamental frequency,
 the second harmonic is called
 the 1st overtone
 the third harmonic is called
 the 2nd overtone, and so forth.
 The 1st overtone is NOT the same as the 1st harmonic!!!!
 the fundamental frequency,
 the 1st overtone
 the 2nd overtone, and so forth.
 Magnetism

Think of Magnetism as analogous to ___, with these (3) changes

Think of Magnetism as analogous to ___, with these (3) changes
 Magnetism=analogous to ELECTRICITY, with these changes:
 Replace (+) charges with NORTH poles
 Replace () charges with SOUTH poles
 Magnetic Field lines go from North⇒South, instead of Positive⇒Negative
 Replace (+) charges with NORTH poles
 Replace () charges with SOUTH poles
 Magnetic Field lines go from North⇒South, instead of Positive⇒Negative
 Define a system NOT in equilibrium
 How is solving these problems different than solving for equilibrium problems?
 How is solving these problems different than solving for equilibrium problems?
 any problem where the object in question has a NONZERO ACCELERATION
 aka Net Force is NOT zero
 Solved in the same way as an equilibrium problem, but you add "ma"to the losing side
 By adding ma to the weaker side we are making them equal again
 aka Net Force is NOT zero
 By adding ma to the weaker side we are making them equal again
 Circuits
 Switches
 Symbol=?
 Compare open vs. closed switches
 Switches
 Symbol=?
 Compare open vs. closed switches
 Symbol: a diagonal break in the line b/t circuit components
 Open switch

NO electron flow
 Closed switch
 electrons flow
 NO electron flow
 electrons flow
 Torque & Lever Arms
 What are the 3 formulas we need to remember?
 in most cases, what should we simply use what equation?
 What are the 3 formulas we need to remember?
 in most cases, what should we simply use what equation?
 T=Fl
 T=mgl
 T=Frsinθ
 when force applied isnt perpendicular
 θ isnt 90º
 rsinθ=l, but only when θ=90º
 You can usually just use T=Fl
 when force applied isnt perpendicular
 θ isnt 90º
 Circuits
 Capacitors
 what do capacitors do?
 What is their symbol?
 Formulas
 Capacitance
 PE stored by a capacitor
 Capacitors
 what do capacitors do?
 What is their symbol?
 Formulas
 Capacitance
 PE stored by a capacitor
 capacitors store energy and charge by holding electrons on plates separated by a very small distance
 Symbol: 2 vertical lines of equal length
 Formulas:
 Capacitance
 C=Q/V
 PE stored by a capacitor
 U=½CV^{2}^{} ^{}
 Solve C=Q/V for the missing variable, then plug it into the above equation
 U=½CV^{2 }looks a lot like the KE formula!
 Capacitance
 C=Q/V
 PE stored by a capacitor
 U=½CV^{2}^{} ^{}
 Solve C=Q/V for the missing variable, then plug it into the above equation
 U=½CV^{2 }looks a lot like the KE formula!
 U=½CV^{2}^{} ^{}
 Define Heat Energy
 what are the 2 common forms you'll see on the MCAT?
 What is the term "Heat Energy" almost interchangeable with?
 what are the 2 common forms you'll see on the MCAT?
 What is the term "Heat Energy" almost interchangeable with?
 Energy dissapated as heat
 on the MCAT, this usually is heat dissapated from a:
 collision , or
 curentcarrying wire
 "Heat Energy" ≈ "Internal Energy"
 on the MCAT, this usually is heat dissapated from a:
 collision , or
 curentcarrying wire
 Circuits
 Capacitance
 Affect on capacitance: Increasing...
 Plate area
 Plate thickness
 distance b/t plates
 strength of the dialectric
 voltage
 Capacitance
 Affect on capacitance: Increasing...
 Plate area
 Plate thickness
 distance b/t plates
 strength of the dialectric
 voltage
 Affect on capacitance: Increasing...

Increasing plate area increases capacitance because there is more room available on the inside surface of the plate to store electrons.
 Electrons do not line up on the sides or back of the plate, so increasing plate thickness will have no effect on capacitance.

Increasing the distance between the plates increases voltage for a given Q on the plates, which decreases capacitance according to C = Q/V.

Increasing the strength of the dielectric increases capacitance because the dielectric impedes the buildup of the electric field between the plates and diverts some of the capacitor’s finite energy storage capacity to realign dipoles inside the dielectric.

Increased voltage, increases the charge stored but does not increase capacitance, which is the charge stored per voltage.
 Sound
 Pitch
 Define
 What kind of term is "pitch?"
 what is pitch closely related to?
 Higher pitch=?
 Pitch
 Define
 What kind of term is "pitch?"
 what is pitch closely related to?
 Higher pitch=?
 Pitch is the "perception" of frequency by the human ear
 Closely related to frequency, but NOT IDENTICAL
 Is a musical (not scientific) term
 Sounds with HIGHER PITCH have:

higher frequencies

Sounds with LOWER PITCH have:
 lower frequencies
 higher frequencies
 lower frequencies
 Deriving Electric Field equations
 Strength of the Electric Field
 Strength of the Electric Field
 For gravity near earth, g=F/m (from F=mg)
 for a constant elec field:

E=F/q (or E=V/d)
 For "real" gravity, g=Gm/r^{2}
 for a pointcharge elec field:
 E=Kq/r^{2}
 for a constant elec field:
 E=F/q (or E=V/d)
 for a pointcharge elec field:
 E=Kq/r^{2}
 Lenses & Mirrors
 What type of lens is found in:
 the human eye
 a magnifying glass
 What type of lens is found in:
 the human eye
 a magnifying glass
 The lens of the human eye is a converging lens.
 It creates a real (inverted) image of the object onto the retina.
 A magnifying glass is also a converging lens
 It creates a real (inverted) image of the object onto the retina.
 Waves
 The Doppler Effect
 Color Shifts
 How can the Doppler Effect shift colors?
 The Doppler Effect
 Color Shifts
 How can the Doppler Effect shift colors?
 Color Shifts
 If the Dopper Effect causes an INCREASE in frequency (or DECREASE in λ):

White light shifts BLUE
 If the Dopper Effect causes an DECREASE in frequency (or INCREASE in λ):

White light shifts RED
 White light shifts BLUE
 White light shifts RED
 Light
 Visualizing photons as "light packets," predict which way light will bend at both boundaries in the scenarios below:
 Visualizing photons as "light packets," predict which way light will bend at both boundaries in the scenarios below:
 Waves
 Superposition of Waves
 Standing Waves
 describe what creates nodes, antinodes, and properties of standing waves
 Superposition of Waves
 Standing Waves
 describe what creates nodes, antinodes, and properties of standing waves
 Standing Waves
 is a special case of simultaneous CONSTRUCTIVE AND DESTRUCTIVE interference b/t 2 waves
 have identical frequencies moving through the same medium in opposite directions
 At points of maximum destructive interference, waves cancel entirely to create a "node"
 At points of maximum constructive interference, the waves ADD completely to form an "antinode"
 Result:
 is a waveform in which the areas b/t the nodes appear to OSCILLATE up & down b/t crests and troughs
 A standing wave exhibits NO net transport of energy, and does not itself propagate
 basically, theres no translational mvmt of nodes or antinodes in either direction
 When a standard Traveling wave propagates, the minima & maxima move translationally in the direction of propagation
 have identical frequencies moving through the same medium in opposite directions
 is a waveform in which the areas b/t the nodes appear to OSCILLATE up & down b/t crests and troughs
 basically, theres no translational mvmt of nodes or antinodes in either direction
 When a standard Traveling wave propagates, the minima & maxima move translationally in the direction of propagation
 Electric Fields
 What are the 2 types of electric fields?
 Name & describe
 What are the 2 types of electric fields?
 Name & describe
 Point Charge Fields
 equate to "real" gravity, or gravity in space
 A point charge field is an electric field created by a point charge
 The strength of the electric field varies with the distance (r) from the point charge.
 Constant Electric Fields
 equate to "assumed" gravity, or gravity near earth
 is constant
 its strength does NOT vary with distance
 equate to "real" gravity, or gravity in space
 A point charge field is an electric field created by a point charge
 The strength of the electric field varies with the distance (r) from the point charge.
 equate to "assumed" gravity, or gravity near earth
 is constant
 its strength does NOT vary with distance
 Circuits
 What do you need to do before you can solve for a circuit using Ohm's Law (V=IR)?
 What do you need to do before you can solve for a circuit using Ohm's Law (V=IR)?
 Create a simple circuit
 Circuits
 Resistors
 Symbol=?
 What always happens when current, I, flows through a resistor?
 What is "Internal Resistance?"
 What is current flow like through parallel resistors?
 Resistors
 Symbol=?
 What always happens when current, I, flows through a resistor?
 What is "Internal Resistance?"
 What is current flow like through parallel resistors?
 Symbol=zigzag line
 There is ALWAYS a voltage drop across a resistor when current flows through it
 Internal Resistance
 batteries experience internal resistance dur to the (inherent) resistivity of their internal components
 This results in a voltage drop, and therefore DECREASES (slightly) THE TERMINAL VOLTAGE OF THE BATTERY
 Current flow through parallel resistors is always inversely proportional to resistance
 if one resistor has 2X the resistance, it will receive ½ the current
 batteries experience internal resistance dur to the (inherent) resistivity of their internal components
 This results in a voltage drop, and therefore DECREASES (slightly) THE TERMINAL VOLTAGE OF THE BATTERY
 if one resistor has 2X the resistance, it will receive ½ the current
 Machines
 Pulleys
 Formula=?
 What should you be cautious for?
 Pulleys
 Formula=?
 What should you be cautious for?
 F_{m}= mg/ (# of vertical ropes directly lifting the mass)
CAUTION:
 Not every rope that is vertically oriented should be counted and entered into the above equation
 To be counted, a vertical section of rope must life the mass directly
 either by being attached TO the mass, or
 by lifting a pulley that is attached to the mass
 To test, imagine grabbing ONLY THAT ROPE and pulling it upward. Would the mass lift?
 Electromagnetic Spectrum
 All of these waves (RMIVUXG) are ___?
 Longer wavelength=?
 Shorter wavelength=?
 All of these waves (RMIVUXG) are ___?
 Longer wavelength=?
 Shorter wavelength=?

All of these waves are LIGHT!
 Longer wavelength

lower frequency
 LESS ENERGY
 Shorter wavelength

higher frequency
 MORE ENERGY
 lower frequency
 LESS ENERGY
 higher frequency
 MORE ENERGY
 Light
 How should be visualize "photons?"
 Why?
 How should be visualize "photons?"
 Why?

AS PHYSICAL PACKETS OF LIGHT!

Visualize one of these packages striking a flat boundary at an angle.
 It is easy to visualize that one corner of our little “light packet” is going to hit the surface first—before the other corner does.
 If the light is passing from a low index medium to a high index medium, that first corner is suddenly going to be forced to go slower than any other part of the packet that is still in the less dense medium, much like what happens when a car tire goes off the road and hits a soft shoulder.
 The “light packet” will tend to pivot around the corner that is “stuck” in the higherindex medium.
 We can intuit exactly which way the light will bend.
 Visualize one of these packages striking a flat boundary at an angle.
 It is easy to visualize that one corner of our little “light packet” is going to hit the surface first—before the other corner does.
 If the light is passing from a low index medium to a high index medium, that first corner is suddenly going to be forced to go slower than any other part of the packet that is still in the less dense medium, much like what happens when a car tire goes off the road and hits a soft shoulder.
 The “light packet” will tend to pivot around the corner that is “stuck” in the higherindex medium.

Forms of Energy

Elastic PE
Forms of Energy

Elastic PE
 PE_{elastic}= ½kx^{2}
 Lenses & Mirrors
 Lenses (singlelens systems)
 Compare Converging & Diverging lenses
 what do they each usually produce?
 what about when "p" (obj.) is inside the focal point?
 What should you assume about Far away objects? (like the moon)
 Lenses (singlelens systems)
 Compare Converging & Diverging lenses
 what do they each usually produce?
 what about when "p" (obj.) is inside the focal point?
 What should you assume about Far away objects? (like the moon)
 Compare Converging & Diverging lenses
 Converging (aka convex, positive)

USUALLY (!!) produces a positive, real, inverted image
 When "p" is inside the focal point, it produces a negative, virtual, upright image
 Diverging (aka concave, negative)

ALWAYS (!!) produces a negative, virtual, upright image
 Far away objects
 assume the light hitting the lens are all PARALLEL
 As object approaches the lens, the image will no longer be exactly at the focal point f
 USUALLY (!!) produces a positive, real, inverted image
 When "p" is inside the focal point, it produces a negative, virtual, upright image
 ALWAYS (!!) produces a negative, virtual, upright image
 assume the light hitting the lens are all PARALLEL
 As object approaches the lens, the image will no longer be exactly at the focal point f
 Think of ENERGY as...?
 The capacity to do WORK
 Machines
 Force necessary without a machine
 Formula=?
 What's the use of solving for this wrt machines?
 Force necessary without a machine
 Formula=?
 What's the use of solving for this wrt machines?
 F_{necessary}= mg
 Solving for force needed without a machine helps when comparing it to force needed with a machine
 Factors will differ by an exact ratio (e.g. 1:5)
 Factors will differ by an exact ratio (e.g. 1:5)

Forms of Energy

PE stored in a capacitor (3)
Forms of Energy

PE stored in a capacitor (3)
 PE_{capacitor}= ½ QV
 PE_{capacitor}= ½ CV^{2}
 PE_{capacitor}=½Q^{2}/C
 PE_{capacitor}= ½ CV^{2}
 PE_{capacitor}=½Q^{2}/C
 Circuits
 Batteries
 Symbol=?
 Think of batteries as...?
 What do ALL batteries cause?
 Batteries
 Symbol=?
 Think of batteries as...?
 What do ALL batteries cause?
 Symbol: two vertical lines of UNequal length
 Longer line= (+) terminal
 shorter line= () terminal
 Batteries=electron "pumps" that push electrons onto the negative terminal of the battery
 this creates a separation of charge, and therefore a potential difference b/t terminals
 this drives electron flow around the circuit to the positive terminal
 All batteries cause A SEPARATION OF CHARGE
 (which in turn creates a voltage)
 Longer line= (+) terminal
 shorter line= () terminal
 this creates a separation of charge, and therefore a potential difference b/t terminals
 this drives electron flow around the circuit to the positive terminal
 (which in turn creates a voltage)
 Circuits
 Household AC current
 Define:
 "Root mean square current" (RMS)
 what is it, how to calculate, etc.
 Household AC current
 Define:
 "Root mean square current" (RMS)
 what is it, how to calculate, etc.
 The “root mean square” (RMS) method of calculating both voltage and current are necessary for alternating current applications because the current and voltage over time are sinusoidal.
 This creates a problem , because the average of a sine wave centered at the origin is zero.
 If you randomly sampled the voltage in your household wiring it could literally have a voltage of 120V one instant and a voltage of 120V the next instant.
 That would average to zero, even though the alternating current does deliver a continuously useful source of power (It can dissipate energy during both cycles).
 Power companies therefore use the RMS method to calculate the average power delivered to your home
 RMS is just a mathematical calculation and it can be applied to voltage, current, to sine waves, or even to other waveforms such as square waves.
 To find RMS, you take readings at various time intervals, square all of those readings, take the average of those squares (i.e., the mean of the squares) and then take the square root of that average.
 If you randomly sampled the voltage in your household wiring it could literally have a voltage of 120V one instant and a voltage of 120V the next instant.
 That would average to zero, even though the alternating current does deliver a continuously useful source of power (It can dissipate energy during both cycles).
 Power companies therefore use the RMS method to calculate the average power delivered to your home
 RMS is just a mathematical calculation and it can be applied to voltage, current, to sine waves, or even to other waveforms such as square waves.
 To find RMS, you take readings at various time intervals, square all of those readings, take the average of those squares (i.e., the mean of the squares) and then take the square root of that average.
 Electrical Power
 Household Electrical Power
 Name & Describe the 2 types
 Household Electrical Power
 Name & Describe the 2 types
 Alternating Current (AC)
 Both the polarity of the voltage and the direction of the current periodically reverse.
 A graph of current versus time for an AC current creates a sine wave
 Direct Current (DC)
 Direct flow of current through a circuit from positive to negative
 (or in terms of electron flow, from negative to positive).
 DC current is the kind of power used in automobiles because it comes directly from the battery.
 In fact, if something uses a battery you would be perfectly safe on the MCAT to assume that it must be an example of DC current.
 Both the polarity of the voltage and the direction of the current periodically reverse.
 A graph of current versus time for an AC current creates a sine wave
 Direct flow of current through a circuit from positive to negative
 (or in terms of electron flow, from negative to positive).
 DC current is the kind of power used in automobiles because it comes directly from the battery.
 In fact, if something uses a battery you would be perfectly safe on the MCAT to assume that it must be an example of DC current.
 Magnetism
 Formula
 Units
 Formula
 Units
 F=qvBsinθ
 θ=angle between v and B
 Units (of B):
 N*s/C*m OR
 Kg/A*s^{2 }
 θ=angle between v and B
 N*s/C*m OR
 Kg/A*s^{2 }
 Electrical Power
 Formula
 Formula

P=IV
 Just memorize this one
 Solve V=IR for the missing variable, then plug it in to get the other two
 Just memorize this one
 Solve V=IR for the missing variable, then plug it in to get the other two
 Waves
 Intensity
 The Decibel System
 Intensity in dB equation=?
 Intensity
 The Decibel System
 Intensity in dB equation=?
 The Decibel System

Intensity (dB)= 10* log ( I / I_{0 })
 I=intensity of the sound wave in (W/m^{2})
 I_{0}= threshold of human hearing
 I_{0}=1 x 10^{12} W/m^{2}
 will always be given
 I=intensity of the sound wave in (W/m^{2})
 I_{0}= threshold of human hearing
 I_{0}=1 x 10^{12} W/m^{2}
 will always be given
 Define "Internal Energy"
 what relation do nonconservative forces (such as? Give 2 examples) have with internal energy?
 what relation do nonconservative forces (such as? Give 2 examples) have with internal energy?
The energy of:
the internal vibrations
and random motions of molecules and/or atoms
within a system
 Nonconservative forces (such as friction or drag) acting on a moving object results in the transfer of:
KE⇒ INTERNAL ENERGY
 Systems NOT in equilibrium
 2D Forces
 2D Forces
 The system we have outlined simplifies everything into up/down or left/right forces.
 You may well have a force that acts in twodimensions, say at an angle of 30° to the horizontal.
 In such cases simply enter into your table the formula that predicts the component of that force that acts up, down, left or right.
 You may well have a force that acts in twodimensions, say at an angle of 30° to the horizontal.
 In such cases simply enter into your table the formula that predicts the component of that force that acts up, down, left or right.
 Sound
 Harmonics
 Draw diagrams for the first 3 harmonics of:
 a pipe open at one end (antinode) and closed at the other end (node)
 pipe open at both ends
 Harmonics
 Draw diagrams for the first 3 harmonics of:
 a pipe open at one end (antinode) and closed at the other end (node)
 pipe open at both ends
 Draw diagrams for the first 3 harmonics of:
 Mechanical Energy
 Give the formula
 What happens to mechanical energy in the absence of nonconservative forces?
 Give the formula
 What happens to mechanical energy in the absence of nonconservative forces?
 ME=KE+PE

In the absence of noconservative forces, Mechanical Energy is CONSERVED

aka "Total Energy" is conserved
 aka "Total Energy" is conserved
 Wave Speed
 Wave velocity in various mediums
 wave speed (v) is typically equal to the ____ of the medium, divided by ____
 Show this in equation format ^^
 Describe it a bit
 Wave velocity in various mediums
 wave speed (v) is typically equal to the ____ of the medium, divided by ____
 Show this in equation format ^^
 Describe it a bit
 Wave speed is typically equal to the square root of an ELASTIC property of the medium divided by an INTERTIAL property

v = √(elastic/inertial)
 The elastic property is often called a “modulus”.
 The inertial property is a type of density.
 The elastic property is often called a “modulus”.
 The inertial property is a type of density.
 Equilibrium
 Give 5 examples of equilibrium
 Give 5 examples of equilibrium
 Terminal velocity (Fair=mg)
 constant velocity
 Objects at rest
 Balanced fulcrums
 or boards hanging from strings
 Objects floating in a liquid
 or boards hanging from strings
 Snell's Law
 Index of Refraction
 Formula (for I.O.R.)
 Give Formula for Snell's Law
 What does a ray of light being refracted at an interface where n_{2}>n_{1 }look like?
 Index of Refraction
 Formula (for I.O.R.)
 Give Formula for Snell's Law
 What does a ray of light being refracted at an interface where n_{2}>n_{1 }look like?
 Index of Refraction
 n=c/v
 Snell's Law
 n_{1}sinθ_{1}=n_{2}sinθ_{2}
 n=c/v
 n_{1}sinθ_{1}=n_{2}sinθ_{2}
Systems NOT in equilibrium
 Equilibrium on an Inclined Plane
 all forces acting down the plane are ____ _____
 all forces acting up the plane __ _____
 The force down the plane due to gravity is always F = _____
 The force of friction is always ______ to the plane _____the direction of motion.
 There will NEVER be ______ perpendicular to the plane, so you can ignore these forces.
 all forces acting down the plane are “down forces”
 all forces acting up the plane “up forces.”
 The force down the plane due to gravity is always F = mgsinθ.
 The force of friction is always parallel to the plane opposite the direction of motion.
 There will NEVER be acceleration perpendicular to the plane
 so you can ignore these forces.
 so you can ignore these forces.

Forms of Energy

Electrical PE (3)
Forms of Energy

Electrical PE (3)
 PE_{elec}= Kqq/r
 PE_{elec}= qEd
 PE_{elec}= qV
 PE_{elec}= qEd
 PE_{elec}= qV
 Lenses & Mirrors
 Mirrors
 For plane mirrors ONLY, the image q and object p will always be...?
 Mirrors
 For plane mirrors ONLY, the image q and object p will always be...?

EQUAL DISTANCES on either side of the mirror
 Wave Speed
 Wave velocity in various mediums
 Velocity of sound waves in a GAS
 what are the elastic & intertial properties?
 How does increasing these affect V?
 Wave velocity in various mediums
 Velocity of sound waves in a GAS
 what are the elastic & intertial properties?
 How does increasing these affect V?
 Velocity of sound waves in a GAS
 The elastic property is called the “bulk modulus” (B)

directly proportional to BOTH

density and
 temperature
 ∴ for gases, the velocity ends up having this "temperature dependence:"
 v ~ √(T)
 The inertial property is normal density, ρ
 v = √(B/ρ)

directly proportional to BOTH
 density and
 temperature
 ∴ for gases, the velocity ends up having this "temperature dependence:"
 v ~ √(T)
 ∴ for gases, the velocity ends up having this "temperature dependence:"
 v = √(B/ρ)
 Electricity
 Charge
 What "is" a () and (+) charge?
 Charge
 What "is" a () and (+) charge?
 Negative () Charge=electrons
 Positive (+) Charge= relatively FEWER electrons
 Snell's Law
 Total Internal Reflection
 Describe
 What must happen for it to occur?
 Formula
 Total Internal Reflection
 Describe
 What must happen for it to occur?
 Formula
 For light crossing a boundary from a slower to a faster medium (like from glass or water into air), if the angle of refraction would be 90° or more, the incident light does not enter the second medium at all!!

100% of the light is reflected off the boundary and back into the first medium.
 For total internal reflection to occur, the light must be passing from a higher index medium to a lower index medium.
 Formula
 n_{1}sinθ_{1}=n_{2}sin90º SO...
 sinθ_{1}=n_{2}/n_{1}
 100% of the light is reflected off the boundary and back into the first medium.
 n_{1}sinθ_{1}=n_{2}sin90º SO...
 sinθ_{1}=n_{2}/n_{1}
What do TRANSVERSE Mechanical waves require to propagate?
 ∴ they cannot propagate in ____s or ____s
 What's an example of a transverse mechanical wave?
Transverse mechanical waves require a fairly STIFF MEDIUM in order to propagate
 ∴ cannot propagate in liquids or gases
ex: strings on a musical instrument
When solving for Batteries in PARALLEL:
How do you find the TOTAL VOLTAGE?
HINT: It's easy!
Batteries in parallel:
TOTAL voltage=
the HIGHEST voltage of any one of the batteries in parallel
Current, I, flows from ____ to _____ concentrations
 What's the OPPOSITE of Current Flow?
CURRENT FLOW goes from (+)⇒()
ELECTRON FLOW is the opposite ()⇒(+)
Sound
 Sound Resonance
Harmonics (aka "Natural" Frequency)

Explain how one object vibrating near another object can cause them both to be in "RESONANCE", and how "harmonics" factors into all of this

What do 2 objects being in resonance CAUSE?

What in particular that is happening to cause this effect?


When one object is vibrating near another object it can cause the neighboring object
to begin vibrating at that SAME frequency
If the exact frequency at which the second object is caused to vibrate happens to be one of its "natural frequencies" (i.e., harmonics):
the two objects are said to be "in resonance"
 ...and via CONSTRUCTIVE interference can produce a much LOUDER sound!
If the first object causes a vibration in the second object that is NOT a match to one of its natural frequencies, resonance does NOT occur
_____ing _______ is the ONLY WAY you can change RESISTANCE in a circuit
Changing TEMPERATURE is the ONLY WAY you can change resistance in a circuit!
The Doppler Effect
 The answer of the equation will give us is CHANGE IN __?
THIS IS NOT THE ANSWER THEY'LL BE ASKING FOR!!!
 How do you get the ACTUAL value due to the doppler effect?
 HINT: It depends if the relative motion is towards/away from each other...
Δf/f_{s} = v/c
Δλ/λ_{s} = v/c
The answer is of the equation is CHANGE IN λ
 which is often NOT what they're asking for!!
This value must be
added or subtracted from the initial value
in order to get the ACTUAL value
due to the doppler effect
If the relative motion is TOWARDS each other:
 Add to the FREQUENCY
 (subtract from the λ)
If the relative motion is AWAY FROM each other:
 Add to the λ
 (subtract from the frequency)
A parallel plate capacitor charged to 4 x 10^{13}C is allowed to discharge for several seconds until it bears a charge of 2.4 x 10^{13}C
How many electrons flowed off of the capacitor during the discharge?
1.0 x 10^{6}C
4E^{13}  2.4E^{13}=1.6E^{13}
Divide by 1.6E^{19} to get 1E^{6}C
This question requires that you remember the charge on an electron is 1.6 x 10^{19}C

Subtract the final charge from the initial charge and divide by the charge on one electron

to get 1.0 x 10^{6}C

Remember that electron charge is quantized according to 1.6 x 10^{19}C
 In other words, you cannot have a fraction or decimal of an electron
 In practice, the charge of an electron is so small that generally it is not possible to count individual electrons with precision
A 20 Coulomb charged particle is dropped into a parallel plate capacitor with very large and distant plates and experiences a force of 250 N
The distance between the plates is 2.0 meters
What is the voltage across the capacitor?
25V
E=F/q OR E=V/d
To answer this question you must remember that the strength of a field ("E") is defined by:
 the force it can exert on a given charge,
 expressed in:
 Newtons /Coulomb or

Volts /meter
 (Why? Remember that V = Ed, solve for E)
 expressed in:
Calculate E using N/C
 set that number equal to V/m
 then solve for V
The frequency of ANY harmonic is equal to?
__ x ___ ____
n*fundamental frequency
"Fundamental Frequency"= FIRST harmonic object resonates at
(e.g., if the first harmonic is exactly 200 Hz, the 2nd is 400 Hz, the 3rd is 600 Hz, etc.)
 The first harmonic is called
 the _____ _______
 the second harmonic is called
 the___ _____
 the third harmonic is called
 the___ _____
 the _____ _______
 the___ _____
 the___ _____
 The first harmonic is called
 the fundamental frequency,
 the second harmonic is called
 the 1st overtone
 the third harmonic is called
 the 2nd overtone, and so forth
 the fundamental frequency,
 the 1st overtone
 the 2nd overtone, and so forth