If the separation between the plates of an isolated charged parallel-plate capacitor is increased slightly, which of the following also increases?
a. the capacitance
b. the stored electrostatic energy
c. the force o attraction between the plates
d. the magnitude of the charge on each plate
e. the magnitude of the electric field in the region between the plates
The answer is B, the stored electrostatic energy, but I can't think of an equation/equations that correspond to this. I know that C=Q/V, C=EoA/dbut I don't see how electrostatic energy would increase too. What is electrostatic energy anyways--is it the Potential difference? Is that what they mean?
a. the capacitance
b. the stored electrostatic energy
c. the force o attraction between the plates
d. the magnitude of the charge on each plate
e. the magnitude of the electric field in the region between the plates
The answer is B, the stored electrostatic energy, but I can't think of an equation/equations that correspond to this. I know that C=Q/V, C=EoA/dbut I don't see how electrostatic energy would increase too. What is electrostatic energy anyways--is it the Potential difference? Is that what they mean?
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I was fuzzy about that term too. But it seems you're right. The definition of electrical potential difference is
Va - Vb = Wab/Qo
where Wab is the work required to move the test charge Qo from a to b.
From the 2 formulas you gave,
Q/V = EoA/d
Q won't change and Eo and A are constants, so they can be lumped together
V = c*d
So to increase the distance between plates would require work because the plates would have opposite charge.
Va - Vb = Wab/Qo
where Wab is the work required to move the test charge Qo from a to b.
From the 2 formulas you gave,
Q/V = EoA/d
Q won't change and Eo and A are constants, so they can be lumped together
V = c*d
So to increase the distance between plates would require work because the plates would have opposite charge.