A hydrogen atom moving at a speed v absorbs a photon of wavelength 122 nm and stops. The value of v is (mass of hydrogen atom `=1.67xx10^(-27)` kg)

Options

A. `3.25 m//sec`
B. `6.25 m//sec`
C. `9.25 m//sec`
D. `12.25 m//sec`

Answer

A

Explanation

By momentum conservation
`mv - (h)/(lambda) =0`
`v=(h)/(m lambda) =(6.6xx10^(-34))/(1.67xx10^(-27)xx122xx10^(-9)) =3.25 m//sec`