Sound waves of wavelength `lambda` travelling in a medium with a speed of `upsilon m//s` enter into another medium where its speed is `2upsilon m//s.` Wavelength of sound waves iin the second medium is

Options

A. `lambda`
B. `lambda//2`
C. `2lambda`
D. `4lambda`

Answer

C

Explanation

Let the frequency in the first medium is f and in the second medium is f . .
Frequency remains same in both the medium
So, `f=f.implies(v)/(lambda)=(v.)/(lambda.)implieslambda.=((v.)/(v))lambda`
`lambda and lambda.`, v and v. are wavelengths and speeds in first and second medium respectively.
So, `lambda.=((2v)/(v))lambda=2lambda`.