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

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=sin(omegat-kx)` So we have A=12
`omega =5`
Rightarrow`k=4`
Here, `(omegat-kx)` is phase difference = `pi/2` `therefore 5t-4t=pi/3`
When `t=0,4x=pi/2cm`
`therefore x=pi/8`cm