The stationary wave`y = 2a sin kx cos omega t` in a closed organ pipe is the result of the superposition of `y = a sin (omega t - kx)`

Options

A. `y= a cos ( omega t+Kx)`
B. `y= a sin ( omega t+Kx)`
C. `y= -a sin ( omega t+Kx)`
D. `y= -a cos ( omega t+Kx)`

Answer

C

Explanation

`y = a sin ( omega t - Kx)` …(1)
This is the incident wave. When it is reflected from a rigid boundary i.e. the closed end of the pipe, there is a phase change of `pi . :. ` the reflected wave will be given by
` y = a sin ( omegat + Kx + pi) = - a sin ( omegat + Kx)` ...(2)
Superposition of the wave (1) and (2) will give the stationary wave.