what should be the velocity of an electron so that its momentum becomes equal to that of a photon of wavelength `5200 Å`

Options

A. `700ms^(-1)`
B. `1000ms^(-1)`
C. `1400ms^(-1)`
D. `2800ms^(-1)`

Answer

C

Explanation

Momentum, `p=mv=(h)/(lamda)`
`v=(h)/(mlamda)=(6.62xx10^(-34))/(9.1xx10^(-31)xx5.2xx10^(-7))`
`=(6.62xx10^(4))/(9.1xx5.2)`
`=1.4xx10^(3)ms^(-1)=1400ms^(-1)`.