Question

A uniformly charged conducting sphere of $4.4\,m$ diameter has a surface charge density of $60\, \mu C\, m^{-2}$. The charge on the sphere is

• A. $7.3 \times 10^{-3}\, C$
• B. $3.7 \times 10^{-6}\, C$
• C. $7.3 \times 10^{-6}\, C$
• D. $3.7 \times 10^{-3}\, C$

Answer 1

Answer: (D)

Here $D = 2r = 4.4\, m$,
or $r=2.2\,m, \sigma=60\,\mu C\,m^{-2}$
Charge on the sphere, $q=\sigma\times4\pi r^{2}$
$=60\times10^{-6}\times4\times\frac{22}{7}\times\left(2.2\right)^{2}=3.7\times10^{-3}\,C$