Physics · Capacitors and R-C Circuits

JEE Main 2026 — 4 April, Morning Shift — Question 14

A parallel plate air capacitor is connected to a battery. The plates are pulled apart at uniform speed v. If x is the separation at any instant, the time rate of change of electrostatic energy is proportional to $x^\alpha$ . The value of $\alpha$ is

Option A:
-2
Correct
Option B:
1
Option C:
-1
Option D:
2

Answer: A

Step-by-step solution

U = (1/2)(ε₀A/x)V² ⇒ dU/dt ∝ -1/x² ⇒ α = -2

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Exam: JEE Main 2026
Paper: 4 April, Morning Shift
Subject: Physics
Chapter: Capacitors and R-C Circuits
Topic: Capacitance and Different types of Capacitors

Consider a circuit with a capacitor (20 μF), resistor (100 Ω) and two identical diodes. Diode forward resistance = 10 Ω. The…

Answer: A

Step-by-step solution

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