A parallel plate capacitor has a uniform electric field \(E\) in the space between the plates. If the distance between the plates is \(d\) and the area of each plate is \(A,\) the energy stored in the capacitor is:

1. \(\dfrac{E^2 Ad}{\varepsilon_0}\) 2. \(\dfrac{1}{2}\varepsilon_0E^2 Ad\)
3. \(\varepsilon_0EAd\) 4. \(\dfrac{1}{2}\varepsilon_0E^2 \)
Subtopic:  Energy stored in Capacitor |
 92%
Level 1: 80%+
AIPMT - 2012
Hints
Links

A capacitor of capacitance \(C\) is fully charged to \(200~\text{V}.\) It is then discharged through a small coil of resistance wire embedded in a thermally insulated block of mass \(0.2~\text{kg}\) and specific heat \(3.5\times10^2~\text{J}~\text{kg}^{-1}~\text{K}^{-1}.\) If the block’s temperature rises by \(0.4~\text{K},\) what is the value of \(C\text{?}\)
1. \(1000\) \(\mu\text{F}\)
2. \(1200\) \(\mu\text{F}\)
3. \(1400\) \(\mu\text{F}\)
4. \(1600\) \(\mu\text{F}\)
Subtopic:  Energy stored in Capacitor |
 82%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.

If a capacitor of capacitance \(C\) is charged by giving it a charge \(Q,\) the potential difference between its plates is observed to be \(V.\) The energy stored in the capacitor is:
1. \(QV\) 2. \(\dfrac{Q}{V}\)
3. \(\dfrac{QV}{2}\) 4. \(\dfrac{Q}{2V}\)
Subtopic:  Energy stored in Capacitor |
 80%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.

advertisementadvertisement

The plates of a parallel plate capacitor have an area of \(90~\text{cm}^2\) each and are separated by \(2.5~\text{mm}.\) The capacitor is charged by connecting it to a \(400~\text{V}\) supply. How much electrostatic energy is stored by the capacitor?
1. \(1.7\times10^{-6}~\text J\) 
2. \(2.12\times10^{-6}~\text J\) 
3. \(2.55\times10^{-6}~\text J\) 
4. \(1.66\times10^{-6}~\text J\) 

Subtopic:  Energy stored in Capacitor |
 78%
Level 2: 60%+
Hints
Links

Energy per unit volume for a capacitor having area \(A\) and separation \(d\) kept at the potential difference \(V\) is given by:
1. \(\dfrac{1}{2} \varepsilon_{o} \dfrac{V^{2}}{d^{2}}\) 2. \(\dfrac{1}{2 \varepsilon_{o}} \dfrac{V^{2}}{d^{2}}\)
3. \(\dfrac{1}{2} C V^{2}\) 4. \(\dfrac{Q^{2}}{2 C}\)
Subtopic:  Energy stored in Capacitor |
 77%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.