A wave in a string has an amplitude of `2 cm`. The wave travels in the `+ve` direction of x axis with a speed of 1`28 ms^-1` and it is noted that `5` complete waves fit in `4 m` length of the string. The equation describing the wave is

Options

A. `y=(0.02)msin(7.85x+1005t)`
B. `y=(0.02)msin(15.7x-2010t)`
C. `y=(0.02)msin(15.7x+2010t)`
D. `y=(0.02)msin(7.85x-1005t)`

Answer

D

Explanation

Find the parameters and put in the general wave equation.
Here, `A=2cm`
direction `=+ve` x-direction
`v=128ms^-1` and `5lamda=4`
Now, `k=(2pi)/(lamda)=(2pixx5)/(4)=7.85`
and `v=(omega)/(k)=128ms^-1`
`impliesomega=vxxk=128xx7.28=1005`
As `y=Asin(kx-omegat)`
`:. y=2sin(7.85x-1005t)`
`=(0.02)msin(7.85x-1005t)`