A star which is emitting radiation at a wavelength of 5000A is approaching the earth with a velocity of `1.50 xx10^(6) m//s` The change in wavelegth of the radiation as received on the earth is

Options

A. `2.5 Å`
B. `25Å`
C. `2.50Å`
D. `0.25Å`

Answer

B

Explanation

According to Doppler effect in light , the change in wavelength is given by
`(d lambda)/(lambda)=(v)/(c) or d lambda= lambda((v)/(c))`
`=5000 xx 10^(-10) xx (1.5 xx 10^(6))/(3 xx 10^(8))`
`=2.5 xx 10^(3-10+6-8)`
`:. ""d lambda=2.5 xx 10^(-9)=25 xx 10^(-10)m=25Å`