Question

The wavelength of the incident wave is $x\pi /a$. Find $x$

Answer 1

On comparing the given expression with $y=Acos(kx+wt)$, we get

$a=k$ where $k=\frac{2\pi }{\lambda }$

Thus $a=\frac{2\pi }{\lambda }$

$⟹\lambda =\frac{2\pi }{a}$ which gives $x=2$