Question

The de Broglie wavelength of an electron and the wavelength of a photon are the same. The ratio between the energy of that photon and the momentum of that electron is ( $c$ is velocity of light, $h$ is Planck's constant)

• A. $h$
• B. $c$
• C. $\frac{1}{h}$
• D. $\frac{1}{c}$

Answer 1

Answer: (B)

According to question, we have
De Broglie wavelength of electron $=$ Wavelength of photon
$\frac{h}{p_{e l e c t r o n}}=\frac{h c}{E_{p h o t o n}}$ , where $p$ is the momentum of electron, $c$ is speed of light, $E$ is energy of photon and $h$ is Planck's constant.
$\frac{E_{p h o t o n}}{p_{e l e c t r o n}}=\frac{h c}{h}=c$