A hydrogen atom is in fifth excited state. When the electron jumps to ground state, the velocity of recoiling hydrogen atom is

• A

  $1.1 \mathrm{m} {\mathrm{s}}^{-1}$
• Correct answer
  B

  $4.2 \mathrm{m} {\mathrm{s}}^{-1}$
• C

  $8.4 \mathrm{m} {\mathrm{s}}^{-1}$
• D

  $11.2 \mathrm{m} {\mathrm{s}}^{-1}$

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