Question

The energy of photon of wavelength $\lambda$ is

[h = Planck's constant, c = speed of light in vacuum]

• A. $hc\lambda$
• B. $\frac{h\lambda }{c}$
• C. $\frac{\lambda }{hc}$
• D. $\frac{hc}{\lambda }$

Answer 1

Answer: (D)

$\frac{hc}{\lambda }$

The energy of a photon is directly proportional to its frequency with proportionality constant being the Plank's constant $h$.

Hence $E=h\nu =h\frac{c}{\lambda }$(Since $c=\lambda \nu$)

$⟹E=\frac{hc}{\lambda }$