RE-NEET 2026 Physics Electric Potential MCQ Question
Consider a fixed uniformly charged insulating sphere with radius R and total charge +Q. A point charge -q (q<<Q) with mass m is released from rest at a distance of 3R from the centre of the charged sphere. When the point charge reaches the surface of the sphere, its speed is : (ε₀ is the permittivity of vacuum, neglect gravitational forces).
√(2Qq/3πε₀mR)
√(Qq/3πε₀mR)
√(Qq/4πε₀mR)
√(3Qq/4πε₀mR)
Correct Answer
Detailed Explanation
Using energy conservation, the potential energy at 3R is converted to kinetic energy at R. Solving for speed v gives v = √(Qq/4πε₀mR).
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