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Physics · Electric Charges and Fields
हिन्दीThree identical metal spheres \( A \), \( B \), and \( C \) are mounted on insulating stands. Sphere \( A \) initially carries a net electric charge of \( +Q \), while spheres \( B \) and \( C \) are uncharged. Sphere \( A \) is first brought into contact with sphere \( B \) and then separated. Next, sphere \( B \) is brought into contact with sphere \( C \) and separated. Finally, sphere \( C \) is brought into contact with sphere \( A \) and separated. The final electric charge remaining on sphere \( C \) is:
Correct answer · Option 3
\( \frac{3Q}{8} \)
Explanation
When identical conducting spheres touch, charge divides equally between them. After A touches B: \( q_A' = q_B' = \frac{Q}{2} \). After B touches C: \( q_B'' = q_C' = \frac{Q/2 + 0}{2} = \frac{Q}{4} \). After C touches A: \( q_C'' = \frac{q_C' + q_A'}{2} = \frac{Q/4 + Q/2}{2} = \frac{3Q}{8} \).
