Question

The ratio of the energies of photons of $2000\AA$ to that of $4000\AA$ is

• A. 2
• B. 4
• C.
• D.

Answer 1

The correct option is A

2

$E=\frac{hc}{\lambda }$

$\Rightarrow \lambda \infty \frac{1}{E}$

$\therefore \frac{{\lambda }_1}{{\lambda }_2}=\frac{E_2}{E_1}=\frac{4000\AA }{2000\AA }$

$\therefore {\lambda }_1:{\lambda }_2=2:1$