Answer to Question #175124 in Electricity and Magnetism for Joshua Musyoki

Question

Consider two 100𝜇𝐹 capacitors. One is charged to 10V, disconnected from the power supply, 

and then connected across the other. Calculate the energy stored by the combination

Answer 1

$W=\frac{C_0 U_0^2}{2},$

$C_0=C_1+C_2=2C,$

$U_0=U_1=U_2=U,$

$W=CU^2,$

$W=100\cdot 10^{-6}\cdot 10^2=0.01~J.$