Q. A heavenly body is receding from earth such that the fractional change in $\lambda$ is 1, then its velocity is
A) $c$
B) $\frac{3c}{5}$
C) $\frac{c}{5}$
D) $\frac{2c}{5}$
Explanation
(a) $\frac{\mathrm{\Delta}\lambda}{\lambda} = \frac{v}{c} \Rightarrow 1 = \frac{v}{c} \Rightarrow v = c$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.