Question

3. A hydrogen atom moving at a speed v absorbs a photon
of wavelength 122 nm and stops. Find the value of u.
Mass of a hydrogen atom = 1.67 x 10^-27 kg.​

Answer 1

Answer:

Given,

wavelength , \lambdaλ = 122 nm = 122\times 10^{-9}122×10

−9

mass of hydrogen, m = 1.67\times 10^{-27}1.67×10

−27

kg

we know that ,

m \times v - p = m(0) = 0m×v−p=m(0)=0

∵ p = \frac{h}{\lambda}p=

λ

h

∴ m\times v = \frac{h}{\lambda}m×v=

λ

h

or,

v = \frac{h}{m\times \lambda}

m×λ

h

v = \frac{6.62\times 10^{-34}}{1.67\times 10^{-27}\times 122\times 10^{-9}}

1.67×10

−27

×122×10

−9

6.62×10

−34

v = 3.25 m/s

Hydrogen atom moving at a speed of 3.25 m/s