An electron of a stationary hydrogen atom (mass = $\mathrm{m}$) jumps from the fifth energy level to the ground level. As a result, the atom emits a photon and recoils with some velocity. The velocity that the atom acquires as a result of photon emission is [$\mathrm{h}$ = Planck's constant, $\mathrm{R}$ = Rydberg's constant]

• Correct answer
  A

  $\frac{24\mathrm{hR}}{25\mathrm{m}}$
• B

  $\frac{25\mathrm{hR}}{24\mathrm{m}}$
• C

  $\frac{24\mathrm{m}}{25\mathrm{hR}}$
• D

  $\frac{25\mathrm{m}}{24\mathrm{hR}}$

Hence, the correct answer is option: 'A'.