A progressive wave is represented by `y = 12 sin (5t - 4x)` cm. On this wave, how far away are the two points having phase difference of `90^circ` ?

Options

A. `pi//4`
B. `pi//8`
C. `pi//16`
D. `pi//32`

Answer

B

Explanation

`k = 4 " " :. (2pi)/(lamda) =4 " " :. lamda = (pi)/(2)`
`delta = (2pix)/(lamda) = (2pi x)/((pi//2)) = 4x`
`:. x = (delta)/(4) = (pi)/(2 xx 4) = (pi)/(8)`