Question

The momentum of a particle of mass m and charge q is equal to that of photon of wavelength λ the speed of the particle is given by:-​

Answer 1

Given:

The momentum of a particle of mass m and charge q is equal to that of photon of wavelength λ.

To find:

Speed of particle ?

Calculation:

• We know that : De-Broglie wavelength of photon is given as : $\boxed{\lambda=\dfrac{h}{P}}$.

• Here 'P = mv' refers to momentum.

Now, as per the question :

$P_{particle} = P_{photon}$

$\implies \: m \times v = \dfrac{h}{ \lambda}$

$\implies \: v = \dfrac{h}{ m\lambda}$

So, the final answer is :

$\boxed{\: v = \dfrac{h}{ m\lambda} }$