0In side a parallel plate capacitor, there is a plate parallel to the outer plates whose thickness is equal to n = 0.7 of the gap width. Dielectric constant of material of the plate is K = 7. When the plate is absent, capacitance of the capacitor equal C = 10 µF. The capacitor was connected to a battery of emf V = 10 volts. Now the capacitor is disconnected from the battery and plate is removed from the gap. After removal of the plate, positively charged plate of the capacitor is reconnected with negative terminal of the same battery and negatively charged plate with positive terminal.
(i) Energy stored in capacitor before reconnection –
Text Solution
Verified by ExpertsCHECK THE SOLUTION.
Ans.
(i)
Sol. C eq = 
= 
When plate was absent
C = 10 µF = 
C eq = 
= 25 µF
* Charge stored = C eq V = 25 × 10 = 250 µCb
* Energy stored = 
× 25 × (10) × (10) = 1250 µJ
After disconnecting the battery plate is removed
- 10 + 
= 0
x = 350 µCb
New charge = – 250 + 350 = 100 µC
New energy = 
= 500 µJ
energy loss:
350 × 10 = U f – U i + Δ H
3500 = 500 – 1250 + Δ H
Δ H = 3500 + 750
= 4250 µJ
(ii)
Sol. C eq = 
= 
When plate was absent
C = 10 µF = 
C eq = 
= 25 µF
* Charge stored = C eq V = 25 × 10 = 250 µCb
* Energy stored = 
× 25 × (10) × (10) = 1250 µJ
After disconnecting the battery plate is removed
- 10 + 
= 0
x = 350 µCb
New charge = – 250 + 350 = 100 µC
New energy = 
= 500 µJ
energy loss:
350 × 10 = U f – U i + Δ H
3500 = 500 – 1250 + Δ H
Δ H = 3500 + 750
= 4250 µJ
(iii)
Sol. C eq = 
= 
When plate was absent
C = 10 µF = 
C eq = 
= 25 µF
* Charge stored = C eq V = 25 × 10 = 250 µCb
* Energy stored = 
× 25 × (10) × (10) = 1250 µJ
After disconnecting the battery plate is removed
- 10 + 
= 0
x = 350 µCb
New charge = – 250 + 350 = 100 µC
New energy = 
= 500 µJ
energy loss:
350 × 10 = U f – U i + Δ H
3500 = 500 – 1250 + Δ H
Δ H = 3500 + 750
= 4250 µJ
Prepare Smarter with CGP Edu
Get practice questions, solutions, and test series in one place.
Write a Review
Share your experience with this question and solution.
Commentary
Send your comment, doubt, correction, or feedback to admin.
Similar Questions
Explore conceptually related problems