Sound Multiple Choice Questions
(a) AB
(b) BD
(c) DE
(d) AE
Ans. (b) BD
Explanation: The distance between two consecutive peaks or two consecutive
troughs is called wavelength. The figure shows one peak and one trough. Sum of
widths of a peak and trough is also same as wavelength; which is AE in this
case. Hence, BD is half the wavelength.
7. Earthquake produces which kind of sound before the main shock wave begins
(a) ultrasound
(b) infrasound
(c) audible sound
(d) none of the above
Ans. (b) infrasound
Explanation: It is due to infrasound that some animals get advanced warning of
earthquake and show strange changes in their behaviour.
8. Infrasound can be heard by
(a) dog
(b) bat
(c) rhinoceros
(d) human beings
Ans. (c) rhinoceros
Explanation: Rhinoceros communicate using infrasound of as low frequency as 5
Hz.
9. Before playing the orchestra in a musical concert, a sitarist tries to adjust
the tension and pluck the string suitably. By doing so, he is adjusting
(a) intensity of sound only
(b) amplitude of sound only
(c) frequency of the sitar string with the frequency of other musical
instruments
(d) loudness of sound
Ans. (c) frequency of the sitar string with the frequency of other musical
instruments Explanation: Frequency of a particular musical instrumental should
be in tune with that of other musical instruments. This helps in production of
pleasant music. That is why artists usually adjust the frequencies at the start
of a musical concert.