Question

A certain capacitor has a capacitance of 12 microfarads when the dielectric is air. The capacitor is charged to 400V and disconnected from the power source. If a dielectric (k=4.0) is inserted, the new voltage will be:

a. 100 V

b. 200 V

c. 800 V

d. 1600 V

Answer 1

When a dielectric is inserted between the plates of a capacitor, the capacitance increases. In this case, the new voltage will be 400V.

Step-by-step explanation:

When a dielectric is inserted between the plates of a capacitor, the capacitance increases. The new capacitance C' is given by C' = k * C, where C is the original capacitance and k is the dielectric constant.

In this case, the original capacitance is 12 microfarads, and the dielectric constant is 4.0. Therefore, the new capacitance after inserting the dielectric is 4.0 * 12 microfarads = 48 microfarads.

The voltage across the capacitor plates remains the same when the dielectric is inserted. Therefore, the new voltage will also be 400V, option (c).