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. 2.75 m/s
B. 3.25 m/s
C. 4.85 m/s
D. 5.65 m/s

Answer

B

Explanation

Linear momentum of photon and electron are equal and opposite
`p = m =(h)/(lambda)`
` v = (h)/(m lambda) = (6.62 xx 10^(-34))/(1.67 xx 10^(-27) xx 122 xx 10^(-19))`
`v = 3.25 ` m/s