Physics Ch 7. Waves and Sound

Question 1

Transverse waves

Answer 1

Have oscillations of wave particles perpendicular to the direction of wave propagation, includes electromagnetic waves

Question 2

Propagation

Answer 2

-

Question 3

Longitudinal waves

Answer 3

Have oscillations of wave particles parallel to the direction of wave propagation, includes sound waves

Question 4

Displacement in a wave

Answer 4

x - In a wave refers to how far appointed as from the equilibrium position expressed as a vector quantity

Question 5

Amplitude in a wave

Answer 5

The magnitude of its maximum displacement

Question 6

Crest

Answer 6

Maximum point of a wave or most positive displacement

Question 7

Trough

Answer 7

Minimum point of a wave or point of most negative displacement

Question 8

Wavelength

Answer 8

Lambda – the distance between two crests or two troughs

Question 9

Frequency

Answer 9

F – the number of cycles per second, expressed in hertz

Question 10

Angular frequency

Answer 10

Omega – another way of expressing frequency but expressed in radians per second

Question 11

Period

Answer 11

T – the number of seconds it takes to complete a cycle, the inverse of frequency

Question 12

Interference

Answer 12

Describe the ways in which waves interact to in space to form a resultant wave

Question 13

Constructive interference

Answer 13

Occurs when waves are in exactly in phase with each other, the amplitude of the resultant wave is equal to the sum of the amplitude of the two interfering waves

Question 14

Destructive interference

Answer 14

Occurs when waves are exactly out of phase with each other, the amplitude of the resultant wave is equal to the difference in amplitude between the two interfering waves

Question 15

Partially constructive or partially destructive interference

Answer 15

Occur when two waves are not quite perfectly inner out of phase with each other, the displacement of the resultant wave is equal to the sum of the displacement of the two interfering waves

Question 16

Traveling waves

Answer 16

Have continuously shifting points of maximum and minimum displacement

Question 17

Standing waves

Answer 17

Produced by the constructive and destructive interference of two waves of the same frequency traveling in opposite directions in the same space

Question 18

Anti-nodes

Answer 18

Points of maximum oscillation

Question 19

Nodes

Answer 19

Points where there is no oscillation

Question 20

Resonance

Answer 20

The increase in amplitude that occurs when a periodic force is applied at the natural or resonant frequency of an object

Question 21

Natural/resonant frequency

Answer 21

-

Question 22

Damping

Answer 22

A decrease in amplitude caused by an applied or non-constructive force

Question 23

Sound

Answer 23

Produced by mechanical disturbance of a material that creates an isolation of the molecules in the material

Question 24

Sound propagation

Answer 24

Sounds propagates faster through solids, followed by liquids, and slowest through gases, within a medium, its density increases, the speed of sound decreases

Question 25

Pitch

Answer 25

Related to the frequency of a sound

Question 26

Doppler effect

Answer 26

A shift in the perceived frequency of a sound compared to the actual frequency of the omitted sound when the source of the sound and it’s detector are moving relative to one another

Question 27

Source and detector moving toward each other

Answer 27

Apparent frequency will be higher than the emitted frequency

Question 28

Source and detector are moving away from each other

Answer 28

Parent frequency will be lower than the emitted frequency

Question 29

Source and detector moving in the same direction

Answer 29

The apparent frequency can be higher, lower, or equal to the emitted frequency when the two objects are moving in the same direction

Question 30

Shock waves/sonic boom

Answer 30

When the source is moving at or above the speed of sound

Question 31

Sound level

Answer 31

Related to sound intensity, intensity is related to a waves amplitude, intensity decreases over distance and some energy is lost to attenuation from frictional forces

Question 32

Strings and open pipes

Answer 32

Open at both ends, support standing waves and the length of the stringer pipe is equal to some multiple of half wave lengths

Question 33

Closed pipes

Answer 33

Closed at one end, also support standing waves in the length of the pipe is equal to some odd multiple of quarter wavelengths

Question 34

Ultrasound

Answer 34

Sounds used medically for both imaging and treatment

Question 35

Wave speed equation

Answer 35

v = f*lambda

Question 36

Period equation

Answer 36

T = 1/f

Question 37

Angular frequency equation

Answer 37

omega = 2pif=2*pi/T

Question 38

Speed of sound equation

Answer 38

v = sqrt(B/rho)

Question 39

Doppler effect equation

Answer 39

fprime=f*(v+/-v_d)/(v-/+v_s)

Question 40

Intensity equation

Answer 40

I = P/A

Question 41

Sound level equation

Answer 41

Beta = 10log(I/I_o)

Question 42

Change in sound level equation

Answer 42

Beta_f = Beta_i +10log(I_f/I_i)

Question 43

Beat frequency equation

Answer 43

f_beat = abs(f_1-f_2)

Question 44

Wavelength of a standing wave in strings and open pipes

Answer 44

lambda = 2L/n

Question 45

Frequency of a standing wave in strings and open pipes

Answer 45

f = nv/2/L

Question 46

Wavelength of a standing wave in a closed pipe

Answer 46

lambda = 4*L/n

Question 47

Frequency of a standing wave in a closed pipe

Answer 47

f = n*v/4/L