JEE Main 2025 · 28 January · morning · Single correct · +4 / −1
Two capacitors C₁ and C₂ are connected in parallel to a battery. Charge-time graph is shown below for the two capacitors. The energy stored with them are U₁ and U₂, respectively. Which of the given statements is true?
- (a) C₂>C₁, U₂>U₁
- (b) C₁>C₂, U₁>U₂
- (c) C₂>C₁, U₂<U₁
- (d) C₁>C₂, U₁<U₂
Answer and solution
Answer (a) C₂>C₁, U₂>U₁
Solution
Physics sir · 4 steps
Ignore how fast each curve climbs; read the final charge, because both capacitors end at the same voltage.
- Same voltage. In parallel, both capacitors are connected across the same battery. Once charging is over, each has the battery voltage V across it.
- Read the graph. The steady value each curve levels off at is the final charge. C₁ rises faster at first, but C₂ levels off higher, so Q₂ > Q₁.
C = Q/V, U = 1/2QV
- Compare both. With V the same, more charge means more capacitance, so C₂ > C₁. Energy U = 1/2QV also grows with Q, so U₂ > U₁.
- So. C₂ > C₁ and U₂ > U₁, which is option (a).
The idea to keep. For capacitors in parallel, V is common, so both C and U go up with the final charge. On a q–t graph, the plateau decides this, not the early slope.
Answer from the NTA final answer key. Solution by PrepWiser.