Which kind of sound is produced in an earthquake before the main shock wave begins?

A. ultrasound B. infrasound

C. audible sound

D. none of the above

In SONAR we use:

A. ultrasonic waves

B. infrasonic waves

C. radio waves

D. audible sound waves

When we change a feeble sound to a loud sound, we increase its:

A. frequency B. amplitude

C. velocity D. wave length

Before playing the orchestra in a musical concert, a sitarist tries to adjust the tension and pluck the strings 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

‘Note’ os a sound:

A. of a mixture of several frequencies

B. of mixture of only two frequencies

C. of a single frequency

D. always unpleasant to listen to