Question

The momentum of a photon is $2\times {10}^{-16}gm-cm/sec$. Its energy is

• A. $0.61\times {10}^{-26}erg$
• B. $2.0\times {10}^{-26}erg$
• C. $6\times {10}^{-6}erg$
• D. $6\times {10}^{-8}erg$

Answer 1

The correct option is D

$6\times {10}^{-8}erg$

$p=\frac{E}{c}\Rightarrow E=p\times c=2\times {10}^{-16}\times (3\times {10}^{10})=6\times {10}^{-6}erg.$