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Electricity and Magnetism

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Moderate

Energy Stored in Capacitors after Being Joined in Parallel

EANDM-QLJUGY

Two capacitors with values $C_1 =25.0 \:\mu \rm F$ and $C_2 = 60.0 \:\mu \rm F$ each carry a charge $Q_1 = Q_2 = 12 \:\mu \rm C$. The two capacitors are joined in parallel with the higher voltage sides of each individual capacitor being connected to each other in the parallel combination.

What is the energy stored in the charged capacitors before they are connected in parallel, $E_B$, and the total energy stored in the parallel capacitor pair after they are connected in parallel, $E_A$?

A

$E_B =4.08 \:\mu \rm J$
$E_A=4.08\:\mu \rm J$

B

$E_B =2.04 \:\mu \rm J$
$E_A=1.69\:\mu \rm J$

C

$E_B =15.7 \:\mu \rm J$
$E_A=14.2\:\mu \rm J$

D

$E_B =4.08 \:\mu \rm J$
$E_A=3.38\:\mu \rm J$

E

$E_B =4.08 \:\mu \rm J$
$E_A=0\:\mu \rm J$