# Need help with A Level physics capacitors question

"After the capacitor is charged it is isolated from the power supply so that the charge stored remains constant. Then the plates are pulled further apart. Explain what happens to the capacitance of the capacitor and hence the energy stored by the capacitor"

So the mark scheme says the capacitance decreases (which I had worked out due to the equation C=Q/V). But it also says that the energy stored therefore increases and I can't work out why this is? Can anyone help please??
You should have found that the capacitance decreases from this equation as it shows that capacitance and distance are inversely proportional: 𝐶 = 𝐴𝜀0𝜀r/d

Energy stored = (1/2)x(Q^2/C), therefore the energy stored would decrease as capacitance increases. These equations are in the AQA data sheet, this might not be relevant to your exam board?
Original post by bertielarter
You should have found that the capacitance decreases from this equation as it shows that capacitance and distance are inversely proportional: 𝐶 = 𝐴𝜀0𝜀r/d
Energy stored = (1/2)x(Q^2/C), therefore the energy stored would decrease as capacitance increases. These equations are in the AQA data sheet, this might not be relevant to your exam board?

Oh, this makes sense, and the equations are relevant to my exam board, thank you!