Energy stored in parallel plate capacitor

In summary, the conversation revolved around solving a question related to a parallel plate capacitor with a charge of 0.040µC on each plate, a potential difference of 240 V, and a separation of 0.20 mm of air. The equations Q/V=eo A/d, Cair=Aeo/d, and E=1/2 CV2 were used to solve the question and the correct result was obtained. However, it was noted that a shorter route could have been taken by using the relationship between charge and potential on a capacitor.
  • #1
xamy
27
0
Can anyone please tell me whether I have solved this question correctly or not.

1. Homework Statement
A parallel plate capacitor has a charge of 0.040µC on each plate with a potential difference of 240 V. The parallel plates are separated by 0.20 mm of air. What energy is stored in this capacitor?

Homework Equations


Q/V=eo A/d
Cair=Aeo/d
E=1/2 CV2

The Attempt at a Solution


Q/V=eo A/d

A=Qd/Veo

A=(0.040u)(0.20/1000)/(240)(8.85x10-12)

A=3.766x10-3 m2

Cair=Aeo/d

=[3.766x10-3(8.85x10-12)]/(0.20/1000)

=0.1666uF

E=1/2 CV2

=1/2(0.1666u)(240)2

=4.7994uJ
 
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  • #2
You have reached the correct result. But you took a pretty long route to get there. Note that the relationship between charge and potential on a capacitor is Q = C*V. You've been given both Q and V so you could have obtained C directly.
 
  • #3
Alright thankyou!
 

Related to Energy stored in parallel plate capacitor

1. What is a parallel plate capacitor?

A parallel plate capacitor is an electrical component that stores energy by creating an electric field between two conductive plates separated by an insulating material.

2. How is energy stored in a parallel plate capacitor?

Energy is stored in a parallel plate capacitor by the accumulation of electric charge on the plates, which creates an electric field between them. This electric field stores potential energy, which can be released when the capacitor is discharged.

3. How does the distance between the plates affect the energy stored in a parallel plate capacitor?

The energy stored in a parallel plate capacitor is directly proportional to the distance between the plates. As the distance between the plates increases, the electric field decreases, resulting in a decrease in energy stored.

4. What is the formula for calculating the energy stored in a parallel plate capacitor?

The formula for calculating the energy stored in a parallel plate capacitor is E = 1/2 * C * V2, where E is the energy stored in joules, C is the capacitance in farads, and V is the voltage across the capacitor in volts.

5. How does the capacitance of a parallel plate capacitor affect the energy stored?

The capacitance of a parallel plate capacitor is directly proportional to the energy stored. A higher capacitance means the capacitor can store more charge, resulting in a greater energy storage capacity. Capacitance can be increased by increasing the plate area or decreasing the distance between the plates.

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