A wave is propagating along x-axis. The displacement of particles of the medium in z-direction at t=0 is given by : `z= exp[-(x+2)^(2)]` where 'x' is in meter. At t=1s, the same wave disturbance is given by `z=exp[-(x-2)^(2)]`. Then the wave propagation velocity is :-

Options

A. 4 m/s in + x direction
B. 4 m/s in - x direction
C. 2 m/s in + x direction
D. 2 m/s in - x direction

Answer

A

Explanation

Let wave equation be
`z=e^(-[x-v(t-t_(0))]^(2))`
At `t =0,x+vt_(0)=x+2rArrvt_(0)=2`
At `t=1s,x-v(1-t_(0))=x-2rArr v=+4m//s`