An electron with energy $0.1\mathrm{keV}$ moves at right angle to the earth's magnetic field of $1\times {10}^{-4}{\mathrm{Wbm}}^{-2}$. The frequency of revolution of the electron will be
(Take mass of electron $=9.0\times {10}^{-31} \mathrm{kg}$)

• A

  $1.6\times {10}^5 \mathrm{Hz}$
• B

  $5.6\times {10}^5 \mathrm{Hz}$
• Correct answer
  C

  $2.8\times {10}^6 \mathrm{Hz}$
• D

  $1.8\times {10}^6 \mathrm{Hz}$

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