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Waves - Multiple Choice Questions

Q1. Two points on a progressive wave are one-eighth of a wavelength apart.

The distance between them is 0.5 m, and the frequency of the oscillation is 10 Hz.

What is the minimum speed of the wave?

A
0.2 m s−1
B
10 m s−1
C
20 m s−1
D
40 m s−1

 

λ = 8 x 0.5m = 4.0 m

c = fλ = 4.0 x 10 = 40 m s−1

Q2. Which of the following waves cannot be polarised?

A
radio
B
 ultrasonic
C
microwave
D
 ultraviolet

 

Sound waves are longitudinal and cannot be polarised the others are transverse electromagnetic waves.

Q3. Which of the following is correct for a stationary wave?

A
 Between two nodes the amplitude of the wave is constant.
B
 The two waves producing the stationary wave must always be 180° out of phase.
C
 The separation of the nodes for the second harmonic is double the separation of nodes for the first harmonic.
D
 Between two nodes all parts of the wave vibrate in phase.

 

Q4. Sound waves cross a boundary between two media X and Y.

The frequency of the waves in X is 400Hz.

The speed of the waves in X is 330 ms −1 and the speed of the waves in Y is 1320 ms –1 .

What are the correct frequency and wavelength in Y?

 
Frequency / Hz
Wavelength / m
A
100
0.82
B
400
0.82
C
400
3.3
D
1600
3.3

 

Frequency does not change when the wave passes into another medium.

c = fλ

λ =c/f

λ = 1320 /400 = 3.3 m