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Flashcards in Test 3 Deck (81):
1

Sine Curve

the waveform traced by simple harmony motion, which can be made visible on a moving conveyor belt by a pendulum swinging at right angles above the moving belt.

2

Amplitude

For a wave or vibration, the maximum displacement on either side of the equilibrium (midpoint) position.

3

Wavelength

The distance between successive crests, troughs, or identical parts of a wave.

4

Frequency

For a vibrating body or medium, the number of vibrations per unit time. For a wave, the number of crests that pass a particular point per unit time.

5

Hertz

The SI unit of frequency. One hertz (symbol Hz) equals one vibration per sound.

6

Period

The time in which a vibration is completed. The period f a wave equals the period of the source and is equal to 1/frequency.

7

Transverse Wave

A wave in which the medium vibrates perpendicularly (at right angles) to the direction in which the wave travels. Light waves and waves on stringed instruments are transverse.
_ _ _ _
/ \ / \ / \ / \
/ \_/ \_/ \_/ \

8

Longitudinal Wave

A wave in which the medium vibrates parallel to (along) the direction in which the wave travels. Sound waves are longitudinal.

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9

Wave Speed

The speed with which waves pass a particular point:
Wave speed = frequency x wavelength

10

Wave Interference

The phenomenon that occurs when two waves meet while traveling along the same medium.

11

Interference pattern

the pattern formed b the superposition of different sets of waves that produces reinforcement in some laces and cancellation in others.

12

Standing wave

A stationary interference pattern formed in a medium when two sets of identical waves pass through the medium in opposite directions.

13

Doppler effect

The shift in received frequency due to the motion of a vibrating source toward or away from receiver.

14

Bow Wave

The V-shaped disturbance created by an object moving across a liquid surface at a speed greater than the wave speed.

15

Shock wave

The cone-shaped disturbance created by an object moving at supersonic speed through a fluid

16

Sonic Boom

the loud sound that results from the incidence of a shock wave.

17

Pitch

The highness of lowness of a tone; related to wave frequency.

18

Infrasonic

Describes a sound that has a frequency too low to be hear by the normal human ear.

19

Ultrasonic

Describes a sound that has a frequency too high to be heard by the normal human ear.

20

Compression

A condensed region of the medium though which a longitudinal wave travels.

21

Rarefaction

A rarefied (of reduced pressure) region of the medium through which a longitudinal wave travels.

22

Reverberation

The persistence of sound, as in an echo, due to multiple reflections.

23

Refraction

the bending of sound or any wave caused by a difference in wave speeds.

24

Forced vibration

The setting up of vibrations in an object by a vibrating force.

25

Natural Frequency

The frequency at which an elastic object tends to vibrate when t is disturbed and the disturbing force is removed

26

Resonance

The response of a body when a forcing frequency matches its natural frequency

27

Interference

A result of superposing different waves, often of the same wavelength. Constructive interference results from crest-to-crest reinforcement; destructive interference results from crest-to-trough cancellation

28

Beats

a series of alternative reinforcements and cancellations produced by the interference of two aves of slightly different frequency, heard as a throbbing effect in sound waves.

29

Pitch

The "highness" or "lowness" of a tone, as on a musical scale, which is principally governed by frequency. A high-frequency vibrating source produces a sound of high pitch; a low-frequency vibrating source produces a sounds f high pitch; a low-frequency vibrating source produces a sound of low pitch.

30

Intensity

The power per square meter carried by a sounds wave, often measured in decibels

31

Loudness

The physiological sensation directly related to sound intensity or volume.

32

Quality

The characteristic sound of a musical instrument or voice, which is governed by the number and relative intensities of partial tones.

33

Partial tone

a single-frequency component sound wave of a complex tone. When the frequency of a partial tone is an integer multiple of the lowest frequency, it is referred to as a harmonic.

34

Fundamental Frequency

The lowest frequency of vibration, or first harmonic, in a musical tone.

35

Harmonic

a partial tone whose frequency is an integer multiple of the fundamental frequency. The second harmonic has twice the frequency of the fundamental, the third harmonic three times the frequency, and so on in sequence.

36

Fourier analysis

A mathematical method that disassembles any periodic waveform into a combination of simple sine waves.

37

Electricity

a general term for electrical phenomena, much like gravity has to do with gravitational phenomena

38

Electrostatics

The study of electric charge at rest (not in motion, as in electric currents).

39

Conservation of charge

Electric charge is neither created nor destroyed. the total charge before an interaction equals the total charge after.

40

Coulomb's Law

the relationship among electrical forcer, charge, and distance:
F = k (q1q2 / d^2)
If the charges are alike in sign, the force is repulsive; if the charges are unlike, the force is attractive.

41

Coulomb

the SI unit of electrical charge. One coulomb (symbol C) is equal to the total charge of 6.25 x 10^18 electrons.

42

Conductor

Any material that has free charged particles that easily flow through it when an electrical force action them.

43

Insulator

A material that does not contain free charged particles and through which charge does not easily flow.

44

Semiconductor

A material with properties that fall between those of a conductor and an insulator and whose resistance can be affected by adding impurities.

45

Superconductor

A material that is a perfect conductor with zero resistance to the flow of electric charge.

46

Charging by contact

the transfer of electric charges between objects by rubbing or simple touching.

47

Charging by induction

the redistribution of electric charges in and on objects caused by the electrical influence of a charged object close by but not in contact.

48

Electrically polarized

the term applied to an atom or molecule in which the charges are aligned so that one side has a slight excess of positive charge and the other side a slight excess of negative charge.

49

Electric field

electrical force per unit of charge.
Electric field = F / q

50

Electric potential energy

the energy a charged object possesses by virtue of its location in an electric field.

51

Electric potential

the electric potential energy per unit of charge, measured in volts; often called voltage:
Voltage = electrical potential energy / charge

52

Capacitor

An electrical device--in its simples form, a pair of parallel conducting plates separated by a small distance--that stores electric charge and energy

53

Potential difference

The difference in electric potential between two points, measured in volts (synonymous with voltage difference or simply voltage).

54

Electric current

the flow of electric charge that transports energy from one place to another, measured in amperes, where 1 A is the flow of 6.25 x 10^18 electrons per second, or 1 coulomb per second.

55

Electrical resistance

the property of material that resists electric current, measured in ohms.

56

Ohm's Law

the statute that the current in a circuit varies in direct proportion to the potential difference or voltage across the circuit and inversely with the circuit's resistance:
Current = voltage / resistance

57

Direct current (dc)

electrically charged particles flowing in one direction only.

58

Alternating current (ac)

Electrically charged particles that repeatedly reverse direction, vibrating about relatively fixed positions, in the US, the vibrational rate is commonly 60 Hz.

59

Electric Power

The rate of energy transfer, or the rate of doing work; the mound of energy per unit time, which can be computed as the product of current and voltage;
Power = current x voltage

60

Series circuit

An electric circuit in which electrical devices are connected along a single loop of wire such that the same current is in each device

61

Parallel Circuit

An electric circuit in which electrical devices are connected in such a way that the same voltage acts across each one, and any single one completes the circuit independently of all the other.

62

Magnetic Force

Between magnets, it is the attraction of unlike magnetic poles for each other and the repulsion between like magnetic poles.

63

Magnetic field

The region of magnetic influence around a magnetic pole or moving charged particle.

64

Magnetic domains

Clustered regions of aligned magnetic atoms. When these regions themselves are aligned with one another, the substance containing them is a magnet.

65

Electromagnet

A magnet whose field is produced by an electric current. It is usually in the form of a wire coil with a piece of iron inside the coil.

66

Cosmic rays

High-speed particles that travel throughout the universe.

67

Faradays' Law

The induced voltage in a coil is proportional to the product of its numbers of loops, the cross-sectional area of each loop and the rate at which the magnetic field changes within those loops

68

Generator

An electromagnetic induction device that produces electric current by rotating a child within a stationary magnetic field. a generation converts mechanical energy to electric energy.

69

Transformer

A device for transferring electric power from one coil of wire to another, by means of electromagnetic induction, for the purpose of transforming one value of voltage into another.

70

Electromagnetic wave

and energy-carrying wave emitted by a vibrating charge (often electrons) that is composed of oscillating electric and magnetic fields that regenerate one another.

71

Electromagnetic spectrum

The range of electromagnetic waves extending in frequency from radio waves to gamma rays.

72

Transparent

the property of materials to pass light in straight lines without being scattered.

73

Opaque

The property of materials not to allow passage of light (opposite of transparent)

74

Shadow

A shaded region that appears where light rays are blocked by an object

75

Umbra

The darker part of a shadow where all the light is blocked

76

Penumbra

A partial shadow that appears where some but not all of the light is blocked.

77

Solar eclipse

An event in which the Moon blocks light from the Sun and the Moon's shadow falls on part of Earth

78

Lunar eclipse

An event in which the Moon passes into the shadow of Earth.

79

Additive Primary Colors

Red, blue, and green

80

Complementary Colors

Any two colors of equal brightness that, when added, produce the sensation of white light.

81

Subtractive primary colors

Absorbing pigments: magenta, yellow, and cyan