A point source emits sound equally in all directions in a non-absorbing medium. Two point P and Q are at a distance of 9 meter and 25 meter, respectively, from the source. The ratio of amplitudes of the wave at P and Q is

Options

A. `5 : 3`
B. `sqrt(5) : sqrt(3)`
C. `3 : 5`
D. `25 : 9`

Answer

A

Explanation

`IpropA^(2)andI prop(1)/(2)piRL`
`(I_(1))/(I_(2))=(R_(2))/(R_(1))=(A_(1)^(2))/(A_(2)^(2))rArr(A_(1))/(A_(2))=sqrt((R_(2))/(R_(1)))=sqrt((25)/(9))=5:3`.