Electrostatics Question 606
Question: A 20F capacitor is charged to 5V and isolated. It is then connected in parallel with an uncharged 30F capacitor. The decrease in the energy of the system will be [EAMCET 2001]
Options:
A) 25 J
B) 200 J
C) 125 J
D) 150 J
Show Answer
Answer:
Correct Answer: D
Solution:
$ \Delta U=\frac{C _{1}C _{2}}{2(C _{1}+C _{2})}{{(V _{1}-V _{2})}^{2}} $
$ =\frac{20\times 30}{2(20+30)}{{(5-0)}^{2}}=150J $
