MHT CET · Physics · Capacitance
When the battery across the plates of a charged condenser is disconnected and a dielectric slab is introduced between its plates then the energy stored
- A becomes infinity
- B does not change
- C increases
- D decreases
Answer & Solution
Correct Answer
(D) decreases
Step-by-step Solution
Detailed explanation
Since the battery is disconnected, the charge on the capacitor remains constant. When the dielectric slab is introduced, the capacitance increases \(\mathrm{k}\) times.
Energy stored, \(\mathrm{U}_{\mathrm{i}}=\frac{\mathrm{q}^2}{2 \mathrm{C}}\)
\(
\mathrm{U}_{\mathrm{f}}=\frac{\mathrm{q}^2}{2 \mathrm{kC}} < \mathrm{U}_{\mathrm{i}}
\)
Energy stored, \(\mathrm{U}_{\mathrm{i}}=\frac{\mathrm{q}^2}{2 \mathrm{C}}\)
\(
\mathrm{U}_{\mathrm{f}}=\frac{\mathrm{q}^2}{2 \mathrm{kC}} < \mathrm{U}_{\mathrm{i}}
\)
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