A oil drop having a mass $4.8 \times 10^{-10} \mathrm{~g}$ and charge $2.4 \times 10^{-18} \mathrm{C}$…

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 : $\left(g=10 \mathrm{~ms}^{-2}\right)$
  1. $5 \mathrm{~ms}^{-2}$
  2. $10 \mathrm{~ms}^{-2}$
  3. $15 \mathrm{~ms}^{-2}$
  4. $20 \mathrm{~ms}^{-2}$

Solution

$a=\frac{F}{m}=\frac{q E}{m}=\frac{m g}{m}$ $g=10 \mathrm{~m} / \mathrm{s}^2$

Asked in: AP EAMCET 2006

Practice more Electrostatics questions on Aicharya