Question

Two conducting spheres having radii 10 cm and 20 cm. One sphere has given charge of $150\mu C$ and it is connected by a wire to another sphere. Their common potential will be:

• A. $9\times {10}^6$ volt
• B. $4.5\times {10}^6$ volt
• C. $1.8\times {10}^6$ volt
• D. $1.35\times {10}^9$ volt

Answer 1

The correct option is D $1.35\times {10}^9$ volt

electrostatic potential charges $\to$ formally disturbed.

$v_1=9\times {10}^9\times \frac{150\times {10}^{-6}}{0.1}=135\times {10}^{5}v$

$v_2=9\times {10}^9\times \frac{150\times {10}^{-6}}{0.2}\Rightarrow 67.5\times {10}^{5}v$

$v=9\times {10}^9\times \frac{q_1}{0.1}=9\times {10}^9\times \frac{q_2}{0.2}$

Since total charge remains the same

$2\times 15\times {10}^{-5}=q_1+q_2=\frac{v(0.1+0.2)}{9\times {10}^9}$

$v=1.35\times {10}^9$ volt