A progressive wave travels in a medium `M_(1)` and enters into another mediun `M_(2)` in which its speed decreases to `60%`. Then the ratio of the amplitude of the transmitted and the incident waves is

Options

A. `3//5`
B. `3//4`
C. `3//10`
D. `1`

Answer

B

Explanation

`v_(2) = (60)/(100)v_(1) = (3)/(5)v_(1)`
`(A_(t))/(A_(i)) = (2v_(2))/(v_(1) + v_(2)) = (2(v_(2))//(v_(1)))/(1 + ((v_(2))/(v_(1)))) = (2(3//5))/(1 + (3//5)) = (3)/(4)`