Question

A star is moving away from the Earth with speed $V$. Change in wavelength $\left(d\lambda \right)$ observed on Earth is.

• A. $\lambda V/C$
• B. $\lambda V/(C+V)$
• C. $\lambda C/(C+V)$
• D. $\lambda C/V$

Answer 1

The correct option is A $\lambda V/C$

Change in wavelength can be written as $d\lambda =\frac{V\lambda }{C}$

where $c$ is speed of light.