Question

The radius of solid metallic non-conducting sphere is $60cm$ and charge on the sphere is $500\mu C$ . The electric field at a distance $10cm$ from centre of sphere is:

• A. $2\times {10}^{6}N/C$
• B. $2\times {10}^{8}N/C$
• C. $5\times {10}^{6}N/C$
• D. $5\times {10}^{8}N/C$

Answer 1

Answer: (A)

The point $10cm$ from centre of sphere will be inside the sphere. Hence,
$E_{inside}=\frac{1}{4\pi {\epsilon }_0}.\frac{qr}{R^3}$ e
Here, $q=500\times {10}^{-6}C,r=10cm=0.1m$
$R=60cm=0.60m$
$\therefore$ $E_{inside}=(9.0\times {10}^9)\times \frac{500\times {10}^{-6}\times 0.1}{{(0.60)}^3}$
$=2\times {10}^{6}N/C$