If the velocity of the revolving electron of ${\mathrm{He}}^{+}$ in the first orbit $(\mathrm{n}=1)$ is $\mathrm{v},$ the velocity of the electron in the second orbit is:

• A

  $\mathrm{v}$
• Correct answer
  B

  $0.5\mathrm{v}$
• C

  $0.25\mathrm{v}$
• D

  $2\mathrm{v}$

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