Question

An electron experience a force equal to its weight when placed in an electric field. The intensity of the field will be:

• A. $1.7\times {10}^{-11}N/C$
• B. $5.0\times {10}^{-11}N/C$
• C. $5.5\times {10}^{-11}N/C$
• D. 56 N/C

Answer 1

Answer: (C)

$5.5\times {10}^{-11}N/C$

Force acting on electron is given by:
$F=qE$
$\Rightarrow E=\frac{F}{q}=\frac{mg}{e}$
$=\frac{9\times {10}^{-31}\times 9.8}{1.6\times {10}^{-19}}$
$=5.5\times {10}^{-11}N/C$