Two identical copper spheres A and B have charges q each. A third copper sphere C, of the same size but uncharged is brought in contact with the sphere A and then brought in contact with the sphere B and finally removed from both. What is the final charge on C ?

Question

Two identical copper spheres A and B have charges q each. A third copper sphere C, of the same size but uncharged is brought in contact with the sphere A and then brought in contact with the sphere B and finally removed from both. What is the final charge on C ? (A) (q/4) (B) (q/2) (C) (3 q/4) (D) (3 q/5)

Tardigrade Admin · Accepted Answer

On touching sphere A the C -sphere acquires a charge (q/2). Then on touching the sphere B, their total charge, namely (q+(q/2))=(3 q/2) is shared equally. So sphere C acquires (3 q/4) finally.

Q. Two identical copper spheres $A$ and $B$ have charges $q$ each. A third copper sphere $C,$ of the same size but uncharged is brought in contact with the sphere $A$ and then brought in contact with the sphere $B$ and finally removed from both. What is the final charge on $C ?$

$\frac{q}{4}$

$\frac{q}{2}$

$\frac{3 q}{4}$

$\frac{3 q}{5}$

On touching sphere $A$ the $C$ -sphere acquires a
charge $\frac{q}{2}$ . Then on touching the sphere $B$ , their total charge,
namely $(q + \frac{q}{2}) = \frac{3 q}{2}$ is shared equally. So sphere $C$
acquires $\frac{3 q}{4}$ finally.

Q. Two identical copper spheres A and B have charges q each. A third copper sphere C, of the same size but uncharged is brought in contact with the sphere A and then brought in contact with the sphere B and finally removed from both. What is the final charge on C?

4q​

2q​

43q​

53q​