Oscillations and Waves Flashcards
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
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
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
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
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
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.
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
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
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
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
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
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
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
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
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)
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
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
A pulse is sent down a string fixed at one end. Which one of the following diagrams best represents the reflected pulse?
C
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
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
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
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
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
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
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
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
On which one of the following graphs is the wavelength and the amplitude a of a wave correctly represented?
D
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
The variation with time t of the separate displacements d of a point in a medium due to two waves are shown below.
The waves are superposed. Which of the following diagrams shows the variation with time t of the resultant displacement d of the point in the medium?
A
A loudspeaker emits sound of frequency f. The sound waves are reflected from a wall. The arrangement is shown below.
When a microphone is moved along the line SW, minimum loudness of sound is detected at points P, Q and R. There are no other minima between these points. The separation of the minima is d.
The speed of the sound wave is
A. (1/2) fd
B. f/d
C. fd
D. 2fd
D. 2fd
The graph below shows the variation of air pressure with distance along a wave at one given time. The arrow indicates the direction of travel of the wave.
The air pressure at point P is
A. increasing.
B. decreasing.
C. constant.
D. zero.
B. decreasing
Sound waves move faster in warm air than in cold air. The diagram below shows plane waves in cold air moving towards a boundary with warm air.
Which of the arrows shows the possible direction of waves after reaching the boundary?
A. I
B. II
C. III
D. IV
C. III
Diagram 1 below shows the displacement of part of a medium through which a wave is travelling at time t = 0. Diagram 2 shows the displacement at a later time t = 4.0 s in which the wave has moved
forward 10 cm. In this time, the point P on the wave has moved from a crest through zero displacement to a trough
The wavelength of the wave is
A. 5.0 cm.
B. 10 cm.
C. 20 cm.
D. 40 cm.
C. 20 cm
The diagram below shows a pulse travelling along a rope from X to Y. The end Y of the rope is tied to a fixed support
When the pulse reaches end Y it will
A. disappear.
B. cause the end of the rope at Y to oscillate up and down.
C. be reflected and be inverted.
D. be reflected and not be inverted.
C. be reflected and be inverted.
A source produces water waves of frequency 10 Hz. The graph shows the variation with horizontal position of the vertical displacement of the surface of water at one instant in time.
The speed of the water waves is
A. 0.20 cm s−1
.
B. 4.0 cm s−1
.
C. 10 cm s−1
.
D. 20 cm s−1
.
D
A bat approaches an insect of wing span length d. The bat emits a sound wave. The bat detects the insect if the sound is reflected from the insect.
The insect will not be located if
A. the insect’s speed is less than the speed of the sound wave.
B. the insect’s wing beat frequency is greater than the frequency of the sound wave.
C. the length d is much greater than the wavelength of the sound wave.
D. the length d is much smaller than the wavelength of the sound wave
D. the length d is much smaller than the wavelength of the sound wave.
The diagram below shows a transverse wave on a string. The wave is moving from right to left.
In the position shown, point X has zero displacement and point Y is at a position of maximum displacement. Which one of the following gives the subsequent direction of motion of point X and
of point Y?
D
Light is incident on an air-glass boundary as shown below.
Which one of the following is a correct statement of Snell’s law?
A. sinP= constant × sinR
B. sinP= constant × sinS
C. sinQ= constant × sinR
D. sinQ= constant × sinS
D. sinQ= constant × sinS
A string is held horizontally with one end attached to a fixed support. Two pulses are created at the free end of the string. The pulses are moving towards the fixed support as shown in the diagram
below.
Which one of the following diagrams is a possible subsequent picture of the string?
C
A water surface wave (ripple) is travelling to the right on the surface of a lake. The wave has period T. The diagram below shows the surface of the lake at a particular instant of time. A piece of cork is
floating in the water in the position shown. Which is the correct position of the cork a time T/4 later?
A
The diagram below shows a photograph of part of a standing wave on a string that is fixed at both ends. The wavelength of the wave is 40 cm. At a particular time the point marked P has displacement + 2.0 cm and moves with velocity + 80 m s–1.
A second point Q on the string is at a distance of 20cm from P. At the same time that the photograph above was taken, the displacement and velocity of point Q were
displacement velocity
A. + 2.0 cm + 80 m s–1
B. + 2.0 cm – 80 m s–1
C. – 2.0 cm + 80 m s–1
D. – 2.0 cm – 80 m s–1
D
A source of sound is placed near the open end of a cylindrical tube that lies on a horizontal table. The tube has some powder sprinkled along its length. The powder collects in piles along the length
of the tube as shown below.
The distance between two consecutive piles of powder is d and the speed of sound in the tube is v. The frequency of the source is
A. v/2d
B. v/d
C. dv
D. 2dv
A. v/2d
A wave is travelling through a medium. The diagram shows the variation with time t of the displacement d of a particle of the medium from t = 0 to t = 25 ms.
Which of the following correctly gives the frequency and the amplitude of the wave?
frequency / hz amplitude / cm
A. 2.0 x 10–2 2.0
B. 2.0 x 10–2 1.0
C. 50 2.0
D. 50 1.0
D
Waves of frequency f travel with speed c in air and enter a medium M of refractive index 1.5. Which of the following correctly gives the frequency and speed of the waves in the medium M?
A
Plane wavefronts are incident on a barrier as shown below. Which of the following best shows the shape of the wavefronts on the other side of the barrier?
A
Which of the following diagrams best shows the path of a ray of monochromatic light through a glass prism in air?
B
Plane parallel wavefronts are incident on an obstacle. Which of the following diagrams best shows the diffraction of the waves around the obstacle?
B
A vibrating tuning fork is held above the top of a tube that is filled with water. The water gradually runs out of the tube until a maximum loudness of sound is heard. Which of the following best shows the standing wave pattern set up in the tube at this position?
C
The diagram below shows plane wavefronts of a wave that is approaching the boundary between two media, X and Y. The speed of the wave is greater in medium X than in medium Y. The wave
crosses the boundary.
A
The graph below shows the variation with time t of the separate displacements d of a medium, at a particular point in the medium due to two waves, P and Q.
The amplitude of the wave resulting from the interference of P and Q is
A. 0.0 mm.
B. 1.0 mm.
C. 1.4 mm.
D. 2.0 mm.
C. 1.4 mm
