Question

The formula for kinetic mass of photon is:
where $h$ is Planck's constant and $v,\lambda ,c$ are frequency, wavelength and speed of photon respectively.

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

Answer 1

The correct option is B $\frac{h}{c\lambda }$

Energy of the photon is given by,

$E=hv=\frac{hc}{\lambda }$, ...(1)

also for particle of zero mass,

$E=m{c}^2$, ...(2)

form eq(1) and (2) we get,

$m{c}^2=\frac{hc}{\lambda }$

$\therefore$ kinetic mass of photon$=m=\frac{h}{c\lambda }$