Chapter 5

Question 1

Electromagnetic waves

Answer 1

do not require a medium to travel through

includes light

Question 2

Mechanical wabes

Answer 2

require a medium to travel through

includes sound

Question 3

transverse wave

Answer 3

medium is displaced perpendicularly to the direction of wave propagation

Question 4

Longitudinal wave

Answer 4

sound, medium is displaced parallel to the direction of wave propagation

Question 5

velocity of wave

Answer 5

distance the wave travels per unit of time

v= F (wavelength)

Question 6

wavelength

Answer 6

lambda, distance from any point in the wave to the point where the wave begins to repeat itself

Question 7

frequency

Answer 7

number of wavelengths that pass a fixed point in one second

Question 8

Period

Answer 8

T, time it takes the wave to travel the distance of one wavelength

T=1/f

Question 9

What affects the velocity of a wave?

Answer 9

The characteristics of a medium (inertia and elasticity)

Decrease inertia, increase in elasticity will increase velocity

(Increase in IMF, decrease in mass)

Question 10

Elasticity of medium

Answer 10

ability of medium to move back to original shape

more elastic means faster velocity as waves are pushed along

Question 11

Inertia of medium

Answer 11

mediums resistance to motion, more resistance means the wave is slowed down

Question 12

How does velocity of waves change is solid, liquid, and gas

Answer 12

V solid> V liquid> V gas

Question 13

Why do sound waves travel faster in water than in air

Answer 13

water is denser, but has more bulk (more elasticity)

Question 14

amplitude

Answer 14

distance between the X axis and the top of crest or bottom of trough

Always positive

Changes as the wave changes mediums

Question 15

Constructive interference

Answer 15

sum of displacements combine to create a greater displacement

Question 16

destructive interference

Answer 16

sum of displacements results in a smaller displacement

Question 17

Phase

Answer 17

determines what type of interference will occur

Question 18

in phase

Answer 18

two waves with same wavelength and begin at the same point and time

Question 19

out of phase

Answer 19

two waves that have the same wavelength but travel different distances to arrive at the same point

Question 20

Sound

Answer 20

transfer of energy through oscillations between high and low pressure

Question 21

When is sound audible

Answer 21

oscillations in certain frequency trigger electrical impulses to the brain

Question 22

pitch

Answer 22

how high or low a note sounds, corresponds to frequency

Question 23

Power of a wave

Answer 23

rate at which a wave transfers energy

P= delta E over time

measured in intensity

Question 24

intensity

Answer 24

average rate of energy transfer per unit area

Question 25

What affects wave intensity

Answer 25

density of the medium, wave frequency, wave velocity Frequency and amplitude have largest affect (squared)

Question 26

Intensity level

Answer 26

level of loudness ß= 10 log (I/I0) in decibals I0 is the intensity threshold for human hearing if intensity factor increases by 10, the decibals increase by 10

Question 27

Human threshold of hearing

Answer 27

10^-12vW/M^2 20-20,000 HZ

Question 28

Ultrasonic waves

Answer 28

frequency above human hearing US uses high frequency sound waves waves reflect off boundaries and cause vibrations and current which is processed intensity of waves shows density

Question 29

resonance

Answer 29

natural and driving frequency are equal

Question 30

attenuation

Answer 30

dampening, decrease in intensity of wave moving through a medium Bone is denser- waves are reflected in US

Question 31

Doppler effect

Answer 31

change in perceived frequency when a wave source and observer move towards or away from eachother observed> source when moving toward

Question 32

What happens to sound when moving towards source

Answer 32

distance travelled by wave is lesser observer perceives a higher frequency

Question 33

What causes beats

Answer 33

two waves with slightly different frequencies are superimposed alternate constructive and destructive

Question 34

Beat equation

Answer 34

F beat= |F0 - Fs|

Question 35

Shock wave

Answer 35

conical wave produced when the velocity of the sound source exceeds the velocity of the sound wave use mach number

Question 36

Mach number

Answer 36

Vs/v increases as the velocity of sound source increases

Question 37

sonic boom

Answer 37

created by shock wave, as the wave fronts overlap a region of low air pressure forms