# Finding the Energy in a Capacitor and Inductor

7. What is the energy in joules stored in the capacitor below?

The capacitor is shown with 10 volts on each side of it (plus on the left of the capacitor, - on the right), and C = 20 microfarads.

8. What is the energy in joules stored in the inductor shown below?

There is a drawing of an inductor with 7 A flowing to the right, and below is written 7 m H.

https://brainmass.com/engineering/electrical-engineering/finding-energy-capacitor-inductor-116903

#### Solution Preview

The energy U stored in a capacitor with capacitance C under potential drop V is given by:

U = 1/2 * C * V^2

In our case:

V =10v

C ...

#### Solution Summary

This solution provides calculations for finding the energy in a capacitor and inductor. What the energy in joules stored in the inductor is shown is determined.

Compute the energy, voltage and instantaneous power for capacitors and inductors.

Please help with the following problem. Provide step by step calculations for each.

1. What is the energy in a 2 F capacitor at t = pi seconds if v(t) = cos(2t) ?

2. What is the energy in a 10 H inductor at t = pi seconds if i(t) = cos(2t) ?

3. The current flowing through a 1 H inductor is i(t) = 10*cos(20t) amps. Find the voltage.

4. The voltage across a 2 F capacitor is v(t) = 20*e^(-4t) volts. What is the instantaneous power?

5. The current flowing through a 2 H inductor is i(t) = 5*cos(2t) amps. What is the voltage?

6. The charge in a 2 F capacitor varies as q(t) = 20*e^(-4t)*sin(2t) C. What is the voltage?