Question

An electron enters between two horizontal plates separated by $2\, mm$ and having a potential difference of $1000\, V$. The force on electron is

• A. $8 \times 10^{-12} N$
• B. $8 \times 10^{-14} N$
• C. $8 \times 10^{-9} N$
• D. $8 \times 10^{14} N$

Answer 1

Answer: (B)

Force on electron, $F=Q E=Q\left(\frac{V}{d}\right)$
$\Rightarrow F=\left(1.6 \times 10^{-19}\right)\left(\frac{1000}{2 \times 10^{-3}}\right)$
$=8 \times 10^{-14} N$