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Flashcards in Oscillations and Waves Deck (67)
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1

The frequency of oscillation f of a mass m suspended from a vertical spring is given by f= (1/2pi)(k/m)^(1/2)
where k is the spring constant.
Which one of the following plots would produce a straight-line graph?
A. f against m
B. f2 against 1/m
C. f against (m)^(1/2)
D. 1/f against m

B. f2 against 1/m

2

A mass is suspended from a vertical spring. It is set into oscillation by pulling it down a short distance and then releasing it. At which one of the labelled points, during the subsequent motion, will the
acceleration be zero? 

C

3

When light waves travel from air to glass which one of the following happens to the frequency and
wavelength of the light?

           Frequency                  Wavelength

A. stays the same              decreases

B. decreases                       increases

C. stays the same             increases

D. increases                     decreases

A. the frequency stays the same and the wavelength decreases

4

A ray of light travelling in glass is incident on the glass-air boundary at an angle pheta to the normal as shown in the diagram. If pheta is greater than the critical angle which one of the rays best shows the path of the ray?

D

5

Which one of the following correctly places the named parts of the electromagnetic spectrum in order of
increasing wavelength?
A. y-rays, radio waves, x-rays, ultra-violet rays
B. y-rays, x-rays, ultra-violet rays, radio waves
C. radio waves, ultra-violet rays, x-rays, y-rays
D. ultra-violet rays, x-rays, y-rays, radio waves

B. y-rays, x-rays, ultra-violet rays, radio waves

6

The diagram shows two loudspeakers connected to the same signal generator. As a microphone is moved along the path XY a series of maximum and minimum sound levels is detected.

Which one of the following actions on its own will increase the separation between the maximum and
minimum sound levels?
A. Moving the speakers closer to the line XY.
B. Increasing the separation between the speakers.
C. Increasing the amplitude of the sound waves.
D. Decreasing the frequency of the sound waves.

D. Decreasing the frequency of the sound waves.

7

A vibrating string has a length of L. If the speed of the waves in the string is c the frequency of the fundamental mode of vibration of the string will be
A. 2L/c
B. c/L
C. c/2L
D. 2c/L

C. c/2L

8

The diagram represents, at a particular instant of time, a transverse wave travelling to the right along a rope. One section of rope has been marked by tying a ribbon around it at point P.

C

9

Light is incident from air onto on a glass block. What happens to the frequency and wavelength of the light on entering the glass?

                               Frequency                       Wavelength

A.                           changes                                 changes

B.                           changes                              unchanged

C.                           unchanged                         changes

D.                          unchanged                           unchanged

C. frequency doesn't change while wavelength changes

10

Monochromatic light incident on two narrow parallel slits produces a fringe pattern on a screen, with the intensity distribution shown below.

If the same slits were spaced further apart, which of the following diagrams best shows the intensity distribution pattern that would result?

C

11

The diagram below shows ripples on the surface of water at one instant of time. The ripples are moving right to left and a small object, P, is floating in the water. After a quarter of a time period, which letter
correctly shows the position of the floating object?

A

12

Light is refracted at the interface between air and a material as shown below.

The table below lists the value for the sine of various angles.

Angle         0°      30°   45°   60°   90°
Sin (angle) 0.00 0.50 0.71 0.87 1.00
 

Which one of the following is the best estimate for the refractive index of the material?
A. 0.8
B. 1.2
C. 1.4
D. 1.7

C. 1.4

13

Two waves of equal frequency, wavelength and amplitude, A, are travelling along a string towards the same point P as shown below.

If the waves arrive at P at the same time, which of the following best describes the subsequent motion of the string at point P?
A. It will not move.
B. It will oscillate with amplitude A.
C. It will oscillate with amplitude 2 A.
D. It will oscillate with varying amplitude.

A. It will not move

14

An organ pipe is closed at one end and open at the other as shown below.

Which one of the following diagrams correctly shows the positions of the displacement nodes and antinodes when the fundamental standing wave is formed in the tube?

C

15

Water waves at the surface of a pond pass a floating log of length L. The log is at rest relative to the bank. The diagram shows wave crests at one instant.

The number of crests passing the log per unit time is N. The speed of the water waves relative to the log at rest is
A. (L/7)(N-1)

B. (L/6)(N-1)

C. (L/7)N

D. (L/6)N

B. (L/6)(N-1)

16

Two identical triangular pulses of amplitude X travel toward each other along a string. At the instant shown on the diagram below, point M is midway between the two pulses. 

The amplitude of the disturbance in the string as the pulses move through M is
A. 2X.
B. X.
C. X/2
D. 0.

D. 0

17

A person is walking along one side of a building and a car is driving along another side of the building.

The person can hear the car approach but cannot see it. This is explained by the fact that sound waves
A. travel more slowly than light waves.
B. are diffracted more at the corner of the building than light waves.
C. are refracted more at the corner of the building than light waves.
D. are longitudinal waves.

B. are diffracted more at the corner of the building than light waves

18

A pulse is sent down a string fixed at one end. Which one of the following diagrams best represents the reflected pulse?

C

19

Waves can be reflected, refracted and diffracted. Which of these effects can be explained using Huygens’ principle?
A. reflection, refraction and diffraction
B. reflection and refraction only
C. refraction and diffraction only
D. reflection and diffraction only

A. reflection, refraction, and diffraction

20

The displacement d of a particle in a wave varies with distance x along a wave and with time t as shown below.

Which expression gives the speed of the wave?

A.  l/4r

B. l/2r

C. l/r

D. 2l/r

B l/2r

21

A plane wave approaches and passes through the boundary between two media. The speed of the wave in medium 1 is greater than that in medium 2. Which one of the following diagrams correctly shows the wavefronts?

A

22

Two particles X and Y are situated a distance (1/2)λ apart on a stationary wave of wavelength λ. The variation with time t of the displacement of X is shown below.

Which one of the following correctly shows the variation with time t of the displacement of particle Y?

A

23

The diagram shows the variation with distance x along a wave with its displacement d. The wave is travelling in the direction shown.

The period of the wave is T. Which one of the following diagrams shows the displacement of the wave at a time T/4 later?

B

24

When a wave crosses the boundary between two media, which one of the following properties of the wave does not change?
A. Amplitude
B. Wavelength
C. Frequency
D. Speed

C. Frequency

25

A pipe, open at both ends, has a length L. The speed of sound in the air in the pipe is v. The frequency of vibration of the fundamental (first harmonic) standing wave that can be set up in the pipe is

A. v/2L

B. L/2v

C. 4v/L

D. L/4v

A. v/2L

26

Jeremy is walking alongside a building and is approaching a road junction. A fire engine is sounding its siren and approaching the road along which Jeremy is walking. 

Jeremy cannot see the fire engine but he can hear the siren. This is due mainly to
A. reflection.
B. refraction.
C. the Doppler effect.
D. diffraction.

D

27

On which one of the following graphs is the wavelength and the amplitude a of a wave correctly represented?

D

28

Standing waves in an open pipe come about as a result of
A. reflection and superposition.
B. reflection and diffraction.
C. superposition and diffraction.
D. reflection and refraction.

A

29

A source of sound approaches a stationary observer. The Doppler effect may be described by the observer as
A. the increase in loudness of the sound.
B. the increase in wavelength of the sound.
C. the increase in frequency of the sound.
D. the increase in relative speed of the sound waves.

C. the increase in frequency of the sound

30

The diagram below shows two wave pulses moving towards one another.

Which one of the following diagrams shows the resultant pulse when the two pulses are superposed?

B