A wave representing by the equation `y = a cos(kx - omegat)` is superposed with another wave to form a stationary wave such that point `x = 0` is a node. The equation for the other wave is

Options

A. `y=asin(kx-omegat)`
B. `y=-acos(kx+omegat)`
C. `y=-acos(kx-omegat)`
D. `y=-asin(kx-omegat)`

Answer

B

Explanation

Since the point `x=0` is a node and reflection is taking place from point `x=0` This means that reflection nust be taking place from the fixed end and hence the reflected ray must suffer an additional phase change
of `pi` or a path change of `(lamda)/(2)`.
So , if `y_(i ncident)=acos(kx-omegat)`
`impliesy_(refl ected)=acos(-kx-omegat+pi)=-acos(omegat+kx)`