If the potential difference between the plates of a capacitor is increased by 0.1%, the energy stored in the capacitor increases by exactly:
A.) 20%
B.) 22%
C.) 40%
D.) 44%

Please show all the steps.

The ans. should be D.

Question

If the potential difference between the plates of a capacitor is increased by 0.1%, the energy stored in the capacitor increases by exactly:
A.) 20%
B.) 22%
C.) 40%
D.) 44%

Please show all the steps.

The ans. should be D.

anonymous · Answer

the potential energy of a charged capacitor is $$W=CU^2/2$$ where C is a capacitance and U is a potential difference. 1% of U is U/100, then 0.1% is 0.001U. So, if $$Unew=U+0.001U=1.001U$$, then $$Wnew=C(1.001U)^2/2=(1.001)^2CU^2/2=(1.001)^2 W$$. It means tnat W is increased by $$(1.001)^2W-W=0.002001W$$. Hence it is increased by (0.002001)*100%=0.2001%. None of answers match!

anonymous · Answer

i have the same answer like kirill does. After doing reverse technique, i got that it's increasing of voltage is 20%. Maybe something need to be fix in the problem data if you want D as the answer... CMIIW

anonymous · Answer

the equaion for PE stored in a cpacitor is= 1/2 charge o one plate x te potentia differene