Question

A 600 μF capacitor is charged by a 200 V supply. Calculate the electrostatic energy stored in it. It is then disconnected from the supply and is connected in parallel to another uncharged 600 μF capacitor . What is the energy stored in the combination ?

Answer 1

The electrostatic energy stored in a 600 µF capacitor charged by a 200 V supply is calculated using the formula Uc = ½ CV². When connected to another uncharged capacitor in parallel, the voltage across each capacitor is halved, and the energy stored in the combination is recalculated using their total capacitance.

Step-by-step explanation:

To calculate the electrostatic energy stored in a 600 µF capacitor charged by a 200 V supply, we use the formula Uc = ½ CV2, where C is the capacitance and V is the voltage. So, Uc = ½ × 600 µF × (200 V)2. Converting microfarads to farads, we have:

Uc = ½ × 600 µF × 10-6 F/µF × (200 V)2.

When the charged capacitor is disconnected and connected in parallel with another uncharged 600 µF capacitor, the total capacitance becomes 1200 µF, with the voltage across each being 100 V (since charge is conserved and the voltage across each capacitor is now half due to the charge being shared). The energy stored in the combination of capacitors can be calculated as:

Utotal = ½ (C1 + C2) Vfinal2, where C1 = C2 = 600 µF and Vfinal = 100 V. So,
Utotal = ½ × 1200 µF × 10-6 F/µF × (100 V)2.