To make a given sound seem twice as loud, how should a musician change the intensity of the sound? A. Double the intensity
B. Halve the intensity
C. Quadruple the intensity
D. Quarter the intensity
E. Increase the intensity by factor

C. Quadruple the intensity

Explanation:

The intensity of the sound is proportional to square of amplitude of the sound.

I ∝ A²

When the given sound is twice loud as the initial value, then the new amplitude is twice the former.

A₂ = 2A₁

Thus, to make a given sound seem twice as loud, the musician should Quadruple the intensity

b.a device that inputs heat into a cool object