Question

Calculate the change in energy stored in a capacitor of capacitance 1200 μF when the potential difference across the capacitor changes from 50 V to 15 V.

a. 1.125 kJ
b. 0.5625 kJ
c. 1.875 kJ
d. 0.9375 kJ

Answer 1

Therefore, the answer is 1.365 kJ, which none of the options (a) 1.125 kJ, (b) 0.5625 kJ, (c) 1.875 kJ, (d) 0.9375 kJ, match exactly. There might be a mistake in the provided options or the calculations.

Step-by-step explanation:

To calculate the change in energy stored in a capacitor when the potential difference across it changes, we can use the formula for the energy (U) stored in a capacitor:

U = (1/2) C V2

Where:

C is the capacitance

V is the potential difference across the capacitor

First, calculate the initial energy (Ui) with V=50 V:

Ui = (1/2) (1200 x 10-6 F) (50 V)2 = 1.5 J

Then, calculate the final energy (Uf) with V=15 V:

Uf = (1/2) (1200 x 10-6 F) (15 V)2 = 0.135 J

Now, find the change in energy (∆U):

∆U = Uf - Ui = 0.135 J - 1.5 J = -1.365 J

Since energy cannot be negative when discussing absolute quantities, we take the absolute value: |∆U| = 1.365 J, which is equivalent to 1.365 kJ (since 1 J = 0.001 kJ).