Physics MCAT section Flashcards
1
Q
4 assumptions that underlie the ideal gas law and the equation? 1. volume of gas molecules is ________ 2. all collisions are perfectly _______ 3. there are no ________ interactions 4. the temperature is proportional to the _________ of the gas molecules
A
- volume of gas molecules is negligible 2. all collisions are perfectly elastic 3. there are no intermolecular interactions 4. the temperature is proportional to the average kinetic energy of the gas molecules PV= nRT
2
Q
power equation
A
P = E/t E = energy t = time
3
Q
Density equation
A
p = m/V m = mass V = volume
4
Q
capacitance equation
A
C = Q/V Q = charge V = voltage
5
Q
torque equation
A
T = rFsin0
6
Q
electric field equation
A
E = F/q (charge)
7
Q
momentum equation
A
p = mv
8
Q
electric potential equation
A
V = U/q U= electric potential energy
9
Q
what does arctan mean in trigonometry?
A
arctan value = opposite side/adjacent side
10
Q
an object is dropped from the empire state building. what will happen to the acceleration of the object as it experiences air resistance during its downward fall?
A
its acceleration will decrease until the object starts moving with a constant speed. the force of air resistance will increase until its equal in magnitude/opposite direction to the weight of the object.
11
Q
buffer equation
A
Ka = [conjugate base-][strong acid]/[weak acid]
12
Q
pH =
A
-log [strong acid]
13
Q
the bigger the Ka value,
A
the stronger the acid
14
Q
the smaller the pKa value,
A
the stronger the acid
15
Q
buffer equation?
A
pH = pKa + log [A-]/[HA}
16
Q
weak or strong acid? HCl
A
strong
17
Q
weak or strong acid? H2SO4
A
strong
18
Q
weak or strong acid? HNO3
A
strong
19
Q
weak or strong acid? acetic acid (CH3COOH)
A
weak
20
Q
weak or strong acid? HF
A
weak
21
Q
weak or strong acid? oxalic acid (COOH)2
A
weak
22
Q
weak or strong base? sodium hydroxide (NaOH)
A
strong
23
Q
weak or strong base? KOH
A
strong
24
Q
weak or strong base? LiOH
A
strong
25
weak or strong base? NH4OH
weak
26
weak or strong base? NH3
weak
27
for a strong acid titrated with a strong base, what is the pH at equivalence point?
neutral - pH = 7
28
for a weak acid titrated with a strong base, what is the pH at equivalence point?
pH \> 7
29
for a weak base titrated with a strong acid, what is the pH at equivalence point?
pH \< 7
30
how many torr is equal to 1 atm?
760 torr
31
how many J is equal to 1 cal?
4.184 J
32
if heat flows out of the system, what sign does Q have? if heat flows into the system, what sign does Q have? if work is done on the system, what sign does W have? if work is done by the system, what sign does W have?
- + + -
33
how do you calculate K from celsius?
273.15 + celsius
34
0th law of thermodynamics?
if two systems are in thermal equilibrium with a third system, then all three systems are in thermal equilibrium
35
1st law of thermodynamics? 2nd law of thermodynamics? 3rd law of thermodynamics?
law of conservation of energy (U = Q - W) entropy will always increase for a spontaneous rxn entropy in a perfect crystal of any pure substance will always approach 0 as absolute temp approaches 0
36
newtons 1,2,3 laws?
1 - body at rest will remain at rest unless acted on by a force (motion in motion) 2. F = ma 3. Fab = -Fba
37
what is the density of water?
1000 kg/m^3 or 1 g/cm^3
38
what is specific gravity of a fluid?
- density compared to pure density of water SG = p/ 1 g/cm^3
39
pressure equation
P = F/A
40
conversion between torr, atm, and Pa?
1 atm = 760 torr (mmHG) = 1.013x10^5 Pa
41
what is absolute pressure? gauge pressure?
absolute - pressure in a fluid (P = P0 + pgz) P0 = atm at surface z = depth gauge pressure - difference between absolute and atmospheric (Pgauge = P - Patm)
42
what is pascals principle?
for a fluid that is incompressible - a change in pressure will transmit to every part of that fluid and the walls of the containing vessel
43
what is archimedes bouyancy principle?
Fbouy = p of fluid x g x V
44
will an object float or sink with a SG value less than or equal to 1? greater than 1?
less - float greater than 1 - sink
45
what is poeseuilles law? what ratio should you remember from this?
flow rate = (pi)r^4P / 8 (viscosity) L P = inverse of radius to power of 4
46
when talking about turbulent flow, what is eddies? critical speed? boundary layer?
eddies - swirls that form in fluid usually downstream of object critical speed - if flow exceeds this speed turbulent flow occurs boundary layer - the thin layer adjacent to the wall where laminar flow still occurs
47
for fluid in tube of diameter D, what is the equation for critical speed?
vc = NR (reynolds number)x viscosity/ (density x D) reynolds number depends on object
48
continuity equation
Q = v1A1 = v2A2 - indicates that fluid will travel faster in a narrower tube vs a wider tube -velocity and cross sectional area
49
bernoullis equation?
p1 + 1/2 pv^2 + pgh1 = P2 + 1/2pv^2 + pgh2 - explains pressure, height, velocity
50
venturi effect?
combination of bernoulli's and continuity equation -describes relationship between cross-sectional area and pressure - smaller cross sectional area means higher dynamic pressure and lower absolute pressure
51
does venous or arterial circulation hold more blood?
venous, by 3 x
52
how to estimate logs? log (n x 10^m) log (920000000) ?
m + 0.n 8 + 0.92 = 8.92
53
0, 30, 45, 60, 90, 180 - for sin, cos?
sin - 0, 1/2, √2/2, √3/2, 1, 0 cos - 1, √3/2, √2/2, 1/2, 0, -1
54
accuracy (validity) ? precision ?
- ability of instrument to measure true value - ability of instrument to be consistent
55
case-control vs cohort vs cross- sectional studies?
case-control - look at outcomes, then assess risk factors cohort - look at risk factors, assess outcomes cross- sectional - different groups at one single point in time
56
bias vs confounding
bias - error in data collection phase (usually a result of inaccuracy) - BEFORE ANALYSIS confounding - error during analysis, incorrect relationship is characterized
57
internal vs external validity?
internal - ability to reproduce outcomes consistently from an experiment external - ability to reproduce research from experiment and apply it to a population
58
mean vs median vs mode
mean - the average mode - the number that repeats most often median - the number in the middle of data set
59
where is the tail of a positively skewed distribution? negatively skewed?
positively - tail is on the RIGHT negatively - tail is on the LEFT
60
when assessing outliers using interquartile ranges, when is a number considered an outlier?
when the number is more than 1.5 interquartile ranges (IQR = Q3 - Q1) below the first interquartile number or above the 3rd
61
standard deviation? when is a number considered an outlier?
the square root of (xi – mean)2 / n-1 when it is 3 SDs away from the mean
62
for normal distribution, what falls within 1 SD, 2 SD, and 3 SD from the mean?
1 - 68% 2 - 95% 3 - 99%
63
difference between mutually exclusive outcomes and independent/dependent events?
outcomes - dependent on if an event can happen at the same time as another event (flipping a coin can only be heads or tails) independent/dependent events - dependent on if one event will affect another event from happening (rolling a die is independent of the following roll)
64
independent event equation? dependent event equation?
independent - P(A) x P(B) dependent - P(A) + P(B) - P(A) x P(B)
65
in probability, when using the word and - ________ the probabilities when using the word or - __________ the probabilities
and - multiply or - add
66
what is a type I error (a) when talking about hypothesis'? type II (B) error?
I - level of risk we are willing to accept for incorrectly rejecting null hypothesis II - incorrectly fail to reject null hypothesis
67
if p \> a, then do you fail to reject or reject the null hypothesis? if p \< a?
reject the null hypothesis and the statistics are said to be significant fail to reject null hypothesis
68
what is the difference between power and confidence in statistical analysis?
power – the probability of correctly rejecting a false null hypothesis confidence – the probability of correctly failing to reject a null hypothesis
69
slope of a graph =
rise/run = change in y/change in x
70
difference between a linear, semi-log and log-log graph?
linear - axis units will signify 1 unit space (1,2,3..) semi - log - axis ratio is changed while the other axis remains the same (y axis changed to 10^x while x axis remains) in order to make graph linear log-log: axis ratio of both x and y is changed to make the graph linear
71
conversion between C to K? temperature
F = 9/5C + 32 K = C + 273
72
equation for thermal linear expansion
ΔL = aLΔT a = coefficient of linear expansion
73
equation for thermal volume expansion
ΔV = BVΔT B = coefficient of volumetric expansion
74
how are the coefficients of linear and volumetric expansion related?
volumetric (B) = 3a (linear)
75
difference between heat transfer; conduction, convection, radiation?
1. conduction – direct transfer of energy from molecule to molecule through molecular collisions - must have direct physical contact - metals are considered the best conductors because they have metallic bonds that contain a density of atoms and seas of electrons o gases are not, because their atoms are spread out so collisions occur infrequently 2. convection – transfer of heat by physical motion of a fluid over a material - only liquids and gases 3. radiation – transfer of energy by electromagnetic waves - can transfer energy through vacuum
76
what is the specific heat for water?
1 cal/gxK or 4.184 J/gXk
77
heat of transformation equation?
q = mL
78
what does isothermal, adiabatic, isobaric, isovolumetric mean?
isothermal (ΔU = 0) W = Q adiabatic (Q = 0) ΔU = -W isobaric (constant pressure) isovolumetric (W = 0) ΔU = Q
79
what is the internal energy of a system equation?
change in internal energy(ΔU) = Q (heat) - W (work)
80
if work is being done BY a system, what sign does it have (+) or (-)? is internal energy increased or decreased?
+ decrease in total energy, because Q - W
81
what is entropy (second law of thermodynamics?)
ΔS = Qrev/T Qrev = heat that is gained or lost in reversible process entropy is the measurement of spontaneous dispersal of energy at specific temperatures (how spread out) ΔSuniverse = ΔSsurroundings + ΔSsystem \> 0
82
difference between reversible and irreversible processes in physics?
reversible - solid water to liquid water at 0 degrees, system is at equilibrium and no energy is lost or dissipated (amount of entropy gained by system is lost by surrounding) irreversible - coffee cooling down to room temperature (natural)
83
electromagnetic spectrum (longest wave length, lowest energy to shortest wave length, highest energy)
electromagnetic spectrum – radio (109 – 1m), microwave (1 m – 1 mm), infrared (1mm – 700 nm), visible light (700 nm – 400 nm), UV (400 nm – 500 nm), x-ray (50 – 10-2) , gamma rays (\<10-2)
84
electromagnetic waves – ________ waves because oscillating electric and magnetic field vectors are _________ to the direction of propagation
electromagnetic waves – transverse waves because oscillating electric and magnetic field vectors are perpendicular to the direction of propagation
* electric field and magnetic field are also perpendicular to eachother
85
images created by a mirror can be real or virtual. what is the difference between these two?
images created by a mirror can be real or virtual
**real** – if the light actually converges at the position of the image
**virtual** – if the light only appears to be coming from the position of the image but does not actually converge there
(for example, a plane mirror would always created a virtual image)
86
relationship between focal length, radius of curvature, distance between the object/mirror and distance between the image/mirror?
1/f = 1/o + 1/i = 2/r
87
magnification equation?
m = -i/o
88
if magnification is ‘-‘, image is
if magnification is ‘+’, image is
if |magnification| is \> 1, image is
if |magnification| is \< 1, image is
if magnification is ‘-‘, image is inverted
if magnification is ‘+’, image is upright
if |magnification| is \> 1, image is bigger than object
if |magnification| is \< 1, image is smaller than object
89
why will a image never be produced when an object sits at the focal point infront of a concave mirror?
\*\* AN OBJECT THAT SITS AT THE FOCAL POINT WILL NEVER PRODUCE AN IMAGE BECAUSE THE REFLECTED LIGHT WILL BE PARALLEL AND NEVER CONVERGE
90
converging mirrors:
* if object is behind focal point (farther away from mirror than focal point), image will be
* if object is at focal point,
* if object is in front of focal point, image will be
diverging mirrors:
* object will always be behind focal point (farther away from mirror than focal point), image will be
converging mirrors:
* if object is behind focal point (farther away from mirror than focal point), image will be inverted, magnified and real
* if object is at focal point, no image will be produced
* if object is in front of focal point, image will be upright, magnified and virtual
diverging mirrors:
* object will always be behind focal point (farther away from mirror than focal point), image will be upright, virtual and reduced
91
snell’s law ?
From snell’s law, if light enters a medium with a higher index of refraction, light will bend ______ the normal
snell’s law – n = c/v
n = index of refraction
c = speed of light in vacuum
v = speed of light in medium
* n = 1 in a vacuum*
* n \>1 in anything other than a vacuum*
From snell’s law, if light enters a medium with a higher index of refraction, light will bend TOWARD the normal
92
**total internal reflection** - at what incidence angle will this occur
light will emerge from medium if critical angle is ______ than incidence angle
**total internal reflection** – all the light incident on a boundary is reflected back into the original material, which results from any incidence angle that is greater than the critical angle (refracted angle of 90 degrees)
light will emerge from medium if CRITICAL ANGLE IS LARGER THAN THE INCIDENCE ANGLE
93
thin spherical lenses – focal lengths in front of the lens vs back?
converging lenses are _____ in the middle
diverging lenses are ______ in the middle
thin spherical lenses – focal lengths on both side of the lens will be identical
converging lenses are thicker in the middle
diverging lenses are thinner in the middle
94
**real** lenses (where thickness cannot be neglected) – focal length equation?
1/f = (n-1) (1/r1 - 1/r2)
95
**for lenses:**
if the image is on the same side as the object, the image is
if the image is on the opposite side of the lens as the object, the image is
if the object is on the same side of lens as the light source, object is
if the object is on different side as light source, object is
radius and focal length are positive for
radius and focal length are negative for
**for lenses:**
if the image is on the same side as the object, the image is virtual
if the image is on the opposite side of the lens as the object, the image is real
if the object is on the same side of lens as the light source, object is positive
if the object is on different side as light source, object is negative
radius and focal length are positive for converging (convex – thick center of lens)
radius and focal length are negative for diverging (concave – thin center of lens)
96
POWER – measured in what?
equation?
f is in what unit?
since P will be same sign as f, converging lens will have _____ power and diverging lens will have ______ power
nearsighted people will need _____ lenses (in order to see farther away)
farsighted people will need _____ lenses (in order to see closer)
POWER – measured in diopters
P = 1/f
f is in meters\*\*
since P will be same sign as f, converging lens will have positive power and diverging lens will have negative power
nearsighted people will need diverging lenses (in order to see farther away)
farsighted people will need converging lenses (in order to see closer)
97
## Footnote
**hyperopia** –?
**myopia** – ?
**hyperopia** – farsightedness
**myopia** – nearsightedness
98
**MULTIPLE LENS SYSTEMS** – behave as a single lens with equivalent focal length given by:?
power?
magnification?
1/f = 1/f1 + 1/f2 + 1/f3 ...
P = P1 + P2 + P3 ...
m = m1 x m2 x m3 …
99
mirror – focal length is _____ for CONCAVE (CONVERGINGING OR DIVERGIN?)
* focal length is _______ for CONVEX (CONVERGING OR DIVERGING?)
lens – focal length is ______ for CONVEX (CONVERGING OR DIVERGING?)
focal length is ______ for CONCAVE (CONVERGING OR DIVERGING?
mirror – focal length is positive for CONCAVE (CONVERGINGING)
* focal length is negative for CONVEX (DIVERGING)
lens – focal length is positive for CONVEX (CONVERGING)
* focal length is negative for CONCAVE (DIVERGING)
100
will violet light or red light experience more refraction and why?
violet light because the wave lengths are much shorter, so it will bend more (bottom of the rainbow)
101
location of dark fringes (minima) for single slit indicated by?
**location of dark fringes (minima) for multiple slit indicated by?**
location of dark fringes (minima) indicated by:
**asin****θ = n****λ**
**a = width of slit**
**angle between center of lens to dark fringe**
**n = number of the fringe**
**location of dark fringes (minima) indicated by:**
**d sin** **θ = (n+1/2)****λ**
d = distance between slits
angle between the line drawn from midpoint between two slits to the dark fringe and the normal
102
**plane-polarized light** vs unpolarized light?
**plane-polarized light** – electric fields of all the waves are oriented parallel to each other
unpolarized light – electric fields exist in all three dimensions
103
**plane-polarized light** –?
**unpolarized light** –?
**circularly polarized light** – ?
**plane-polarized light** – electric fields of all the waves are oriented parallel to eachother
**unpolarized light** – electric fields exist in all three dimensions
**circularly polarized light** – uniform amplitude but a continuously changing direction causing a helical orientation of the wave
104
what is the relationship between wavelength, speed of light, index of refraction, velocity frequency? (3 different equations)
c = wavelength(frequency)
v = wavelength(frequency)
n = c/v
105
charge is measured in what?
e = ?
charge is measured in coulombs; e = 1.60 x 10-9 C
106
**Insulator** – distrubution of charge on surface?
- electrons linked to nuclei or not?
ex of good insulator?
**Conductors** – distribution of charge on surface?
ex of good conductor?
**Insulator** – not easily distribute a charge over its surface and will not transfer charge to another neutral object
* electrons are closely linked to nuclei (nonmetals)
**Conductors** – charge is dispersed evenly on surface
* transfers and transports charges (electrons can move rapidly throughout the material)
* electrons are loosely attached (metals)
* ionic solutions are also good conductors
107
coulombs law (electrostatic force)?
electric field equation?
Fe = kq1q2/r^2
E = Fe/q = kQ/r^2
108
what is electric potential energy?
what is the equation?
what is electric potential?
electric potential energy: U = kQq/r
* **amount of work necessary** (JOULES) to move a test charge from infinity to a point in space in an electric field surrounding a source charge
electric potential: V = U/q = kQ/r
- measured in VOLTS
109
what does a decrease in electric potential energy indicate about a system? (-4 J to -7 J)
indicates an increase in stability of the system
110
what is voltage and what is the equation for voltage?
voltage is the potential difference between two electric potentials at difference positions
change in voltage = Vb = Va = Wab/q
Wab = the work required to move point a to point b
111
**if you have a positive test charge, it will want to move to a _____ potential energy**
* **it does this by ______ work**
**if you have a negative test charge, it will want to move to a ______ potential energy**
* **it does this be ______ work**
**both electric potentials are working towards a ______ electric potential energy**
**if you have a positive test charge, it will want to move to a LOWER potential energy**
* **it does this by NEGATIVE work**
**if you have a negative test charge, it will want to move to a HIGHER potential energy**
* **it does this be POSITIVE work**
**both electric potentials are working towards a decreasing electric potential energy**
112
**equipotential line** in electrostatics?
**equipotential line** – a line which the potential at every point is the same
* potential difference (voltage) between any two points on an equipotential line is zero
there is only work being done when the point is being moved to a different electric potential (moving to a different orbital), IT DOES NOT MATTER WHAT PATH IS TAKEN TO GET THERE. THE ONLY THING THAT MATTERS IS THE POTENTIAL DIFFERENCE BETWEEN THE TWO LINES
113
dipole moment **?**
**perpendicular bisector of the dipole ?**
net torque on dipole ?
dipole moment **(p) = qd**
**perpendicular bisector of the dipole** – equipotential line that lies halfway between +q and -q
* angle between this plane and dipole axis is 90 degrees (cos90 = 0), so there is no electric potential
net torque on dipole = pEsin ![]()
114
unit for magnetic field – (two) ?
**diamagnetic** – unpaired electrons? magnetic field ?
* magnetism?
* examples?
**paramagnetic** – unpaired electrons? net magnetic dipole moments?
* magnetized?
* examples?
**ferromagnetic** – unpaired electrons? net magnetic dipoles?
* magnetized?
* examples?
unit for magnetic field – tesla (T) or gauss (1 T = 104 gauss)
**diamagnetic** – no unpaired electrons and no magnetic field
* slightly repelled by magnets
* includes woods, plastics, water, glass and skin, etc.
**paramagnetic** – unpaired electrons that have net magnetic dipole moments
* are weakly magnetized, aligning magnetic dipoles to external magnetic field
* removal of magnet causes random reorientation of dipoles
* includes copper, gold
**ferromagnetic** – unpaired electrons that have net magnetic dipoles
* are strongly magnetized when exposed to magnetic field or temperature
* includes iron, nickel, cobalt
115
**long, straight current carrying wire**, magnetic field produced by current I at a perpendicular distance, r, =
B = ?
μ0 = permeability of free space
**circular loop of current carrying wire**
B = ?
**long, straight current carrying wire**, magnetic field produced by current I at a perpendicular distance, r, =
B = μ0I/2πr
μ0 = permeability of free space
**circular loop of current carrying wire**
B = μ0I/2r
* notice the equations are the same, but for long straight, r = any perpendicular distance from wire and for circular loop, r = to the middle of the circle
116
how do you determine where the magnetic field is from a current?
use the right hand rule - point your thumb towards the current and wrap your fingers in and that is the way that the magnetic field is
117
RIGHT HAND rule for magnetic force?
RIGHT HAND RULE
1. position right thumb in direction of velocity vector
2. put fingers in direction of magnetic field lines
3. YOUR PALM will point in direction of POSITIVE MAGNETIC FORCE and the BACK of your hand will point to NEGATIVE MAGNETIC FORCE
118
Magnetic force on a moving charge ?
**Magnetic force on a current-carrying wire/?**
Magnetic force on a moving charge = FB = qvBsin ![]()
* if charge is moving parallel or antiparallel to magnetic field, it experiences no charge
**Magnetic force on a current-carrying wire** = FB = ILBsin ![]()
119
how to get nonzero electric field,?
nonzero magnetic field, ?
nonzero magnetic force,?
nonzero electric field, there must be a charge
nonzero magnetic field, there must be moving particles
nonzero magnetic force, there must be an external electric field acting on a charged particle moving in any direction that isn’t parallel or antiparallel
120
**transverse** waves vs **longitudinal** waves?
**transverse** – direction of particle oscillation is perpendicular to the propagation of the wave (and energy transfer)
* light waves, x-rays, electromagnetic waves
* imagine the ‘wave’ in a stadium
**longitudinal** – particles of wave oscillate parallel to direction of propagation (energy transfer)
* sound waves
121
propagation speed of wave ?
period of a wave?
propagation speed of wave = v = fλ
period – P= 1/f
122
**natural audible frequencies are ?**
**natural audible frequencies are 20 Hz to 20 000 Hz**
123
speed of sound = v = ![]()
B = bulk modulus (resistance to compression – gas being the lowest and solid being the highest)
p = density of medium
sound travels fastest in what medium and slowest in what medium
v = √B/p
## Footnote
B = bulk modulus (resistance to compression – gas being the lowest and solid being the highest)
p = density of medium
sound travels fastest in low-density of solids compared to a dense gas
124
if the source and detector are *moving toward each other*, perceived frequency will be _____ than actual frequency
if the source and detector are *moving away from each other*, perceived frequency will be _____ than actual frequency
if the source and detector are *moving toward each other*, perceived frequency will be greater than actual frequency
if the source and detector are *moving away from each other*, perceived frequency will be less than actual frequency
125
DOPPLER EQUATION
USE THE ____ SIGN CONVENTION WHEN OBJECT IS MOVING TOWARD
USE _______ SIGN CONVENTION WHEN OBJECT IS MOVING AWAY
126
**intensity** of a sound wave?
**intensity** – average rate of energy transfer per area across a surface that is perpendicular to a wave
I = P/A
P = power (watts)
A = area in meters
127
sound level (B) measured in decibels (dB): ??
when intensity of sound is changed by some factor, the new sound level is calculated by ?
sound level (B) measured in decibels (dB): B = 10log(I/Io)
I = intensity
Io = threshold of sound (10^-12)
when intensity of sound is changed by some factor, the new sound level is calculated by
Bf = Bi + 10log(If/Ii)
128
STRINGS: λ =?
open pipe: λ =?
closed pipes: λ= ?
STRINGS: λ = 2L/n
n = number of antinodes
λ = 2L/n
n = number of nodes
closed pipes
λ = 4L/n
n = any positive integer that is an **odd** number!! (1,3,5…)
129
**fundamental frequency** of a standing wave?
**fundamental frequency** – the lowest frequency, or the longest wavelength (because λ = 1/f), of a standing wave
* the first harmonic
130
angular frequency ?
2pi(frequency)
131
in order for a charged molecule to travel towards a CATHODE it must be what charge
positive
132
FURANOSE – __ MEMBERED RING!!
5 - ex. fructose
133
* metabolic alkalosis will result in compensatory ___ breather to try to decrease pH
concentration of CO2 will increase and result in more acidity (lower pH) if not exhaled
* metabolic alkalosis will result in compensatory slow breather to try to decrease pH
134
normal gut flora hang out in what part of the intestines?
cecum
135
energy of a photon of light?
this means that energy is _____ in shorter wave lengths, higher frequency
energy is _____ in longer wave lengths, shorter frequency
kinetic energy of ejected electrons:??
E = hf
E = energy of photon of light
f = frequency of light
this means that energy is higher in shorter wave lengths, higher frequency
energy is lower in longer wave lengths, shorter frequency
kinetic energy of ejected electrons: Kmax = hf – W
W = hft (ft = threshold frequency)
- any additional energy will be converted to kinetic energy
136
FUSION \
FISSION
FUSION – small nuclei combine to form a larger nucleus
FISSION – large nucleus splits into smaller nuclei
* induced by absorption of low energy nuclei
137
ALPHA PARTICLES:? ![]()
* atomic mass/atomic number?
* size
* electrons?
4H
2
* daughter nucleus will have an atomic number two less than before and an atomic mass 4 less than original
* very LARGE and will not penetrate through things
* no electrons
138
BETA DECAY: ?
what is emitted and what happens to atomic mass/number
BETA DECAY: e-
* neutron converted to proton and electron is released
* ATOMIC MASS NUMBER WILL INCREASE BY ONE AND THERE WILL BE NO CHANGE IN MASS
139
GAMMA DECAY?
what happens to atomic mass/number?
GAMMA DECAY: high energy photons
* DOES NOT CHANGE ATOMIC MASS OR NUMBER
* just changes it to a lower state
140
exponential decay equation?
exponential decay: n = noe-λt
141
Current, ? unit?
Current, I = Q/Δt - amp
142
**Kirchhoff’s junction rule** – ?
**Kirchhoff’s loop rule** – ?
**Kirchhoff’s junction rule** – at any point in a circuit, the sum of currents directed into that point equals the sum of currents directed away from point
I(into junction) = I(away from junction
**Kirchhoff’s loop rule** – for a closed circuit, the sum of voltage sources will always equal the sum of voltage (potential) drops
V(source) = V(drop)
143
resistance equation?
R = pL/A
P = resistivity (ohm per m)
144
ohms law?
power?
power of a resistor?
OHMS LAW: V = IR
* voltage drop across resistor will be proportional to the magnitude of the current
POWER: P = ΔE/T
Rate at which energy is dissipated by a resistor is the power of the resistor:
P = IV = I^2(R) = V^2/R
* derived by substituting V for IR (ohms law)
145
series of resistors:?
parallel resistors ?
When two resistors are put in parallel that are identical, what happens to resistance? n resistors?
series of resistors: Vs = V1 + V2 + V3 … and Rs = R1 + R2 + …
parallel resistors: Vp = V1 = V2 = V3 … and 1/Rp = 1/R1 + 1/R2 + …
(resistance will always decrease when more resistors are added in parallel)
When two resistors are put in parallel that are identical, what happens to resistance? It is halved!!! (R/2)
(n/2)
146
**Capacitors** – two plate system where one plate builds up a positive charge (higher potential) and one plate builds up a negative charge (lower potential)
-Q for negative plate
+Q for positive plate
An increase in capacitance results from a ______ in voltage (such that a dielectric metal is introduced between the two plates)
**Capacitors** – two plate system where one plate builds up a positive charge (higher potential) and one plate builds up a negative charge (lower potential)
C = Q/V
-Q for negative plate
+Q for positive plate
An increase in capacitance results from a decrease in voltage (such that a dielectric metal is introduced between the two plates)
147
CAPACITORS IN SERIES ?
CAPACITORS IN PARALLEL ?
CAPACITORS IN SERIES IS OPPOSITE OF RESISTANCE IN SERIES
CAPACITORS IN PARALLEL IS OPPOSITE OF RESISTANCE IN PARALLEL
148
**Galvanic cells** – ?
**electrolytic cells** –?
**Galvanic cells** – spontaneous
* used to do work
* has salt bridge and is separated into half cells
**electrolytic cells** – non-spontaneous
* electrical energy required to induce reaction
149
emf = of a reaction between two half cells?
emf = Ered anode - Ered cathode
150
1 atm = 760 mmHG (torr) = _____ Pa
1 atm = 760 mmHG (torr) = 1.013x105 Pa
151
