Posted by nat on .
Two capacitors, C1=25.0x10^6 and C2=5.0x10^6 are connected in parallel and charged with a 100V power supply.
a)calculate the total energy stored in the 2 capacitors
b) what potential difference would be required across the same 2 capacitors connected in series in order that the combination store the same energy as in a)?
ENERGY STORED=1/2C*DELTA V^2
1/2(25.0e^6 + 5.0e^6)(100)^2
=0.15KJ OR 150J, IS THIS RIGHT? IF NOT HOW DO I GET THE RIGHT ANSWER?
B)1/Ceq= 1/25.0e^6 + 1/5.0e^6= 4.16e^6
DELTA V= SQRT 2x (ENERGY STORED=150J)/
4.16e^6 = 8492v?????? CAN SOMEONE TELL ME IF IM DOING THIS RIGHT?

PHYSICS 
drwls,
The stored energy that you calculate with that formula is in J, not kJ. The answer to the first part is 0.15 J
For the second part, require that
(1/2)Ceq*V^2 = 0.15 J, and solve for V. You are correct that Ceq = 4.167*10^6 F 
PHYSICS 
nat,
so for part two i get 268V is that correct?

PHYSICS 
drwls,
Yes

PHYSICS 
Anonymous,
yes