The amplitude of sound is doubled and the frequency is reduced to one fourth. The intensity of sound at the same point will be

Options

A. increases by a factor of 2
B. decreases by a factor of 2
C. decreases by a factor 4
D. remains unchanged

Answer

C

Explanation

`I_(1) prop A_(1)^(2) n_(1)^(2) and I_(1) prop A_(2)^(2) n_(2)^(2)`
`:. (I_(2))/(I_(1)) = ((2A_(1))^(2))/(A_(1)^(2)) xx ((n_(1)//4)^(2))/(n_(1)^(2)) " " :. I_(1) = (I_(1))/(4)`