What is the energy stored in a capacitor charged to 12 volts with a capacitance of 100 mF?

• A. 1.2 J
• B. 7.20 J
• C. 0.12 J
• D. 14.4 J

Answer: (B)

To find the energy stored in a capacitor, one can use the formula:

[

E = \frac{1}{2} C V^2

]

where (E) is the energy in joules, (C) is the capacitance in farads, and (V) is the voltage in volts.

In this case, the capacitance (C) is given as 100 mF (millifarads), which must be converted to farads:

[

100 , \text{mF} = 0.1 , \text{F}

]

The voltage (V) is given as 12 volts. Now substituting these values into the energy formula:

[

E = \frac{1}{2} (0.1 , \text{F}) (12 , \text{V})^2

]

Calculating ( (12 , \text{V})^2):

[

(12 , \text{V})^2 = 144 , \text{V}^2

]

Now substituting this back into the equation for energy:

[

E = \frac{1}{2} (