Due to Doppler's effect, the shift in wavelength observed is 0.1 Å for a star producing wavelength 6000 Å. Velocity of recession of the star will be

Options

A. 5 km `s^(-1)`
B. 25 km `s^(-1)`
C. 20 km `s^(-1)`
D. 10 km `s^(-1)`

Answer

A

Explanation

(a): `v/c = (Deltalamda)/(lamda)`
`v=c xx (Deltalamda)/(lamda) = 3 xx 10^(8) xx (0.1)/(6000) 5` km `s^(-1)`