Question

What happens to the energy stored in a capacitor connected to a battery when a dielectric is inserted? Was work done in the process?

a) Energy increases; work was done.

b) Energy decreases; work was done.

c) Energy increases; no work was done.

d) Energy decreases; no work was done.

Answer 1

Inserting a dielectric into a capacitor connected to a battery increases the stored energy because the capacitance increases and the voltage remains constant. Work is done during this process as the dielectric is polarized and pulled in.

Step-by-step explanation:

When a dielectric is inserted into a capacitor that is connected to a battery, the energy stored in the capacitor increases. This is because the dielectric material increases the capacitance without changing the voltage, as the battery maintains a constant voltage across the capacitor.

Since the energy stored in a capacitor is given by the formula
`1/2 CV^2`, where C is the capacitance and V is the voltage, increasing capacitance C results in a higher stored energy. Work is done in the process of inserting the dielectric because the capacitor does work on the dielectric as it gets polarized and pulled into the capacitor, thus the correct answer is: a) Energy increases; work was done.