A wave travelling along the x-axis is described by the equation `y(x, t) = 0.005 cos (alpha x - beta t)`. If the wavelength and the time period of the wave are 0.08 m and 2.0 s, respectively, then `alpha and beta` in appropriate units are

Options

A. `alpha=25.00pi,beta=pi`
B. `alpha=(0.08)/(pi),beta=(2.0)/(pi)`
C. `alpha=(0.04)/(pi),beta=(1.0)/(pi)`
D. `alpha=12.50pi,beta=(pi)/(2.0)`

Answer

A

Explanation

`y(x,t)= 0.005cos (alpha x- beta t)`
`(2pi)/(lambda)= alpha` and `(2 pi)/(T)= beta`
So `alpha = (2pi)/(0.08)=25 pi` and `beta = (2 pi)/(2) = pi`.