Q. Two metallic spheres of radii 1 cm and 3 cm are given charges of −1 × 10⁻² C and 5 × 10⁻² C, respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is
A) 2 × 10⁻² C
B) 3 × 10⁻² C
C) 4 × 10⁻² C
D) 1 × 10⁻² C
Explanation
[Solution from source] Total charge = −1 × 10⁻² + 5 × 10⁻² = 4 × 10⁻² C. When connected the spheres reach the same potential, so charge divides in the ratio of radii 1 : 3, giving the bigger sphere ¾ × 4 × 10⁻² = 3 × 10⁻² C. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.