1. Homework Statement [/b]
If the p.d across a capacitor is doubled, by what factor does the ehnergy stored change?

hage567
Homework Helper
What have you done so far? Show your work. What equation might be useful for question #1?

V = Q/C ? i dont really undersatnd the question

hage567
Homework Helper
V = Q/C ? i dont really undersatnd the question

That's not an equation for energy. You want $$U=(1/2)CV^2$$ where U is the stored energy, C is the capacitance, and V is the potential difference.

It's asking if the potential difference is doubled, how much does the energy stored in the capacitor change. So using that equation, if you double V, what happens to U?

ooh ok U doubles

hage567
Homework Helper
ooh ok U doubles

NO, look more closely. It's V squared, right?

increase by 4?

hage567
Homework Helper
That's better.