Exams › JEE Advanced › Physics
A point charge q is held at distance r from the centre of a neutral conducting sphere of radius R (r > R). Consider a point P inside the sphere located at distance r1 from the point charge q. The potential at P due only to the induced charges on the sphere is:
- Kq/r - Kq/r1
- Kq/r1 - Kq/R
- Kq/r1 - Kq/r
- -Kq/r1 + Kq/R
Correct answer: Kq/r - Kq/r1
Solution
A conductor is an equipotential; inside it the total potential is constant and equals the potential at its centre, where the point charge contributes Kq/r and the induced charges contribute zero (they sum to zero net charge and centre is equidistant in the net-zero sense), giving V_total = Kq/r. At point P the point charge q alone contributes Kq/r1. Since V_total = V_q + V_induced, the induced part is V_induced = V_total - V_q = Kq/r - Kq/r1.
Related JEE Advanced Physics questions
- A particle with charge -q and mass m revolves in a circular path of radius r around an infinitely long charged wire with linear charge density +λ. What is the time period of its motion?
- What is the value of the electrostatic potential at point H?
- The electric potential V varies with distance x from a fixed point as follows: V = 5 V for 0 <= x < 10 m, then V decreases linearly from 5 V at x = 10 m to -10 V at x = 20 m. The electric field at x = 13 m is:
- Two capacitors are connected in a circuit with two batteries and a switch S. The system is in steady state with S open. When S is closed, which of the following statements correctly describes the energy exchange?
- In a capacitor bridge circuit, four capacitors C1, C2, C3, and C4 are connected in a bridge configuration with an EMF source E. Capacitor C1 is in the top-left arm, C2 in the top-right arm, C3 in the bottom-left arm, and C4 in the bottom-right arm. Points P and Q are the mid-points (junctions). Find the potential difference V_P - V_Q.
- An isolated charged spherical soap bubble of radius r has the pressure inside equal to atmospheric pressure outside. The surface tension of the soap solution is T. If the total charge on the bubble can be written as N*pi*r*sqrt(2*T/epsilon0), find the integer value of N.
⚔️ Practice JEE Advanced Physics free + battle 1v1 →