Answered

How much electrical potential energy is stored in a capacitor that has [tex][tex]$8.0 \times 10^{-10} C$[/tex][/tex] of charge on each plate and a potential difference across the plates of [tex][tex]$40.0 V$[/tex][/tex]? (Use [tex]PE_{e} = \frac{1}{2} QV[/tex])

A. [tex]1.6 \times 10^{-8} J[/tex]
B. [tex]4.0 \times 10^{-9} J[/tex]
C. [tex]8.0 \times 10^{-9} J[/tex]
D. [tex]3.2 \times 10^{-8} J[/tex]



Answer :

To find the electrical potential energy stored in the capacitor, we can use the formula:

[tex]\[ PE_e = \frac{1}{2} Q V \][/tex]

where:
- [tex]\(PE_e\)[/tex] is the electrical potential energy,
- [tex]\(Q\)[/tex] is the charge on each plate,
- [tex]\(V\)[/tex] is the potential difference across the plates.

Given values:
- [tex]\( Q = 8.0 \times 10^{-10} \, \text{C} \)[/tex]
- [tex]\( V = 40.0 \, \text{V} \)[/tex]

Plug these values into the formula:

[tex]\[ PE_e = \frac{1}{2} \times (8.0 \times 10^{-10} \, \text{C}) \times (40.0 \, \text{V}) \][/tex]

First, perform the multiplication within the parentheses:

[tex]\[ 8.0 \times 10^{-10} \, \text{C} \times 40.0 \, \text{V} = 320.0 \times 10^{-10} \, \text{CV} \][/tex]

Then, multiply by [tex]\( \frac{1}{2} \)[/tex]:

[tex]\[ PE_e = \frac{1}{2} \times 320.0 \times 10^{-10} \, \text{CV} \][/tex]
[tex]\[ PE_e = 160.0 \times 10^{-10} \, \text{J} \][/tex]

Convert [tex]\( 160.0 \times 10^{-10} \, \text{J} \)[/tex] to a more standard scientific notation:

[tex]\[ 160.0 \times 10^{-10} \, \text{J} = 1.6 \times 10^{-8} \, \text{J} \][/tex]

Thus, the electrical potential energy stored in the capacitor is:

[tex]\[ \boxed{1.6 \times 10^{-8} \, \text{J}} \][/tex]

Hence, the correct option is:

A. [tex]\(1.6 \times 10^{-8} \, \text{J}\)[/tex]