Question 696: Electrostats & Capacitance

Question

A capacitor is charged with a battery and energy stored is U. After disconnecting battery another capacitor of same capacity is connected in parallel to the first capacitor. Then energy stored in each capacitor is

Accepted Answer

Let q be the charge on each capacitor.
$$ 	herefore $$ Energy stored,  $$U = {1 \over 2}C{V^2} = {1 \over 2}{{{q^2}} \over C}$$
Now, when battery is disconnected and another capacitor  of same capacity is connected in parallel to the first capacitor, then voltage across each capacitor, $$V = {q \over {2C}}$$
$$ 	herefore $$ Energy stored = $${1 \over 2}C{\left( {{q \over {2C}}} ight)^2} = {1 \over 4}.{1 \over 2}{{{q^2}} \over C} = {1 \over 4}U.$$

Answer

$$U/2$$

Answer

U/4

Answer

4U

Answer

2U

Electrostats & Capacitance

A capacitor is charged with a battery and energy stored is U. After disconnecting battery another capacitor of same capacity is connected in parallel to the first capacitor. Then energy stored in each capacitor is

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