Question

We may state that the energy E of a photon of frequency v is E = hv where h is a Planck’s constant. The momentum P of a photon is $P=\frac{h}{\lambda }$ where $\lambda$ is the wavelength of the photon. From the above statement one may conclude that the wave velocity of light is equal to

• A. $4\times {10}^{5}m{s}^{-1}$
• B. $\frac{E}{p}$
• C. $Ep$
• D. ${\left(\frac{E}{p}\right)}^2$
  
  

Answer 1

The correct option is B $\frac{E}{p}$

E = hv and $p=\frac{h}{\lambda }$
$\Rightarrow \frac{E}{p}=\frac{hv}{h}\lambda =v\lambda =c$