Physics fill in the blanks.

If the amplitude of a sound is halved, its loudness becomes ………………

Complete the following sentence:
The pitch of sound increases if its frequency …………..

Complete the following sentence:
Resonance is a special case of …………….. vibrations, when frequency of the driving force is ……… natural frequency of the body.

Amount of sound energy emitted per unit area normal to the surface is ___________ [loudness/pitch/echo] .

SONAR is a technique used to __________ [determine the size of blue whale/detect the impurities present in sea water/detect the depth of sea bed].

In case of natural vibrations the amplitude and frequency is _________ .[maximum/constant/variable].

Waveform for musical sound is ___________ [uniform/ astounding/ haphazard] .