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

According to question, the progressive wave is represented by `y=12 sin (5t-4x) cm`
Comparing this equation with standard equation of progressive wave,
`y=A sin (omega t-kx)`
So, we have `A=12`
`omega =5 implies k=4`
Here, `(omega t-kx)` is phase difference
`=pi/2 :. 5t-4x=pi/2`
When `t=0, 4x=pi/2`
`:. x=pi/8` cm