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)/(2) cm`
B. `(pi)/(4) cm`
C. `(pi)/(8) cm`
D. `(pi)/(16) cm`

Answer

C

Explanation

`y = 12 sin (5t - 4x)`
Comparing with `y = A sin (omega t - Kx)`
we get `omega = 5 and K = (2pi)/(lamda) = 4`
and phase difference `= (2pi)/(lamda)` (path difference)
`:. (pi)/(2) = 4` (path difference)
`:.` Path difference `= (pi)/(8) cm`