A body sends waves 100mm long through medium A and 0.25m long in medium B. If the velocity of waves in medium A is `80cms^(-1)`, calculate the velocity of waves in medium B.

Options

A. `1ms^(-1)`
B. `2ms^(-1)`
C. `3ms^(-1)`
D. `4ms^(-1)`

Answer

B

Explanation

Here,`lamda_(A)=100mm=0.10m`
`lamda_(B)=0.25 m,v_(A)=80 cms^(-1)=0.80m s^(-1)`
As the frequency of the wave remains same in the two media
`thereforeupsilon=(v_(A))/(lamda_(A))=v_(B)/(lamda_(B))`
`thereforev_(B)=(lamda_(B))/(lamda_(A))xxv_(A)=0.25/0.10xx0.80`
`rArrv_(B)=2ms^(-1)`