1991 - WAEC Physics Past Questions and Answers - page 4
31
Which of the following is not a mechanical wave?
A
wave propagatd in stretched string
B
wave in closed pipe
C
radio waves
D
water waves
correct option: c
Users' Answers & Comments32
Which of the following remains unchanged as light travels from one medium to the other? i. speed. ii. wavelength. iii. frequency.
A
i only
B
ii only
C
iii only
D
i and ii only
correct option: c
Users' Answers & Comments33
Which of the following statements about wave is not correct? i. A wavefront is a line which contains all particles whose vibration are in phase. ii. The direction of propagation of a wave is the link drawn parallel to the wavefront. iii. A wavefront is a circle which is common to particles that are in the same state of disturbance
A
i only
B
ii only
C
i and ii only
D
i and iii only
correct option: e
Users' Answers & Comments34
What type of motion does the skin of a talking drum perform when its being struck with the drum stick?
A
random
B
rational
C
vibratory
D
translational
correct option: c
Users' Answers & Comments35
The sound from a bell in an enclosed jar gradually faints away while the jar is being evacuated. Which of the following explains this observation?
A
the pressue is reduced
B
the sound waves are pumped out
C
the waves are absorbed in the inner walls
D
There is no more material medium
correct option: d
Users' Answers & Comments36
Which of the following statements is true of the diagram shown above?
A
the two point, A and B are in phase
B
distance AB is halgf the wavelength of the wave
C
AC and BD are the amplitude of the wave
D
the two points A and B represents the wave crests
correct option: a
Users' Answers & Comments37
A man standing 300m away from the wall sounds a whistle. The echo from the wall reaches him 1.8sec. later, calculate the velocity of sound in air
A
540.0ms-1
B
333.3ms-1
C
270.0ms-1
D
166.7ms-1
correct option: b
V = \(\frac{2x}{t} = \frac{2 \times 300}{1.8}\)
= 333.33ms-1
Users' Answers & Comments= 333.33ms-1
38
In which of the following is a stationary wave produced? i. A vibrating turning fork held near the end of a resonance tube closed at one end. ii. A string tightly stretched between two points and plucked at its middle. iii. The tuning fork vibrating in air
A
i only
B
ii only
C
i and ii only
D
ii and iii only
correct option: c
Users' Answers & Comments39
A particle of charge q and mass m moving with a velocity v enters a uniform magnetic field b in the direction of the field. The force on the particle is
A
qvB
B
mqvB/m
C
mvB/q
D
O
correct option: d
Users' Answers & Comments40
If the frequency of the e.m.f. source in the a.c. circuit illustrated above is \(\frac{500}{\pi}\)Hz. What is the reactance of the inductor?
A
450
B
0.9
C
900
D
567
correct option: c
x = 2\(\pi f L = 2\pi \times \frac{500}{\pi} \times 0.9\)
= 900\(\Omega\)
Users' Answers & Comments= 900\(\Omega\)