Question

The graph shows the variation of voltage $V$ across the plates of two capacitors $A$ and $B$ versus increase of charge $Q$ stored in them. Which of the capacitors has higher capacitance?

• A. Capacitor $A$
• B. Capacitor $B$
• C. Both (a) and (b)
• D. None of these

Answer 1

Answer: (A)

From the given graphs, find the voltages, $V_{A}$ and $V_{B}$, on capacitors $A$ and $B$ corresponding to charge $Q$ on each of the capacitors. Clearly,
$V_{A}=\frac{Q}{C_{A}} \text { and } V_{B}=\frac{Q}{C_{B}}$
or $\frac{V_{B}}{V_{A}}=\frac{Q / C_{B}}{Q / C_{A}}=\frac{C_{A}}{C_{B}}$
Since, $V_{B} > V_{A}, C_{A} > C_{B}$ i.e., the capacitor $A$ has the higher capacitance.