A oil drop having a mass $4.8 \times 10^{-10} \mathrm{~g}$ and charge $2.4 \times 10^{-18} \mathrm{C}$ stands still between two charged horizontal plates separated by a distance of $1 \mathrm{~cm}$. If now the polarity of the plates is changed, instantaneous acceleration of the drop is : $\left(g=10 \mathrm{~ms}^{-2}\right)$

• A

  $5 \mathrm{~ms}^{-2}$
• Correct answer
  B

  $10 \mathrm{~ms}^{-2}$
• C

  $15 \mathrm{~ms}^{-2}$
• D

  $20 \mathrm{~ms}^{-2}$

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