IB DP Physics Topic 11.3 Capacitors

The circuit diagram shows a capacitor that is charged by the battery after the switch is connected to terminal X. The cell has emf V and internal resistance r. After the switch is connected to terminal Y the capacitor discharges through the resistor of resistance R.

What is the nature of the current and magnitude of the initial current in the resistor after the switch is connected to terminal Y?

• A

• B

• C

• D

Two capacitors of 3 μF and 6 μF are connected in series and charged using a 9 V battery.

What charge is stored on each capacitor?

• A

• B

• C

• D

Three identical capacitors are connected in series. The total capacitance of the arrangement is 1/9 mF. The three capacitors are then connected in parallel. What is the capacitance of the parallel arrangement?

• 1/3 mF

• 1 mF

• 3 mF

• 81 mF

Three identical capacitors, each of capacitance C, are connected as shown.

What is the total capacitance of the combination?

• 2/3 C

• C

• 3/2 C

• 3C

A parallel-plate capacitor is connected to a cell of constant emf. The capacitor plates are then moved further apart without disconnecting the cell. What are the changes in the magnitude of the electric field between the plates and in the capacitance of the capacitor?

• A

• B

• C

• D

Three capacitors, each one with a capacitance C, are connected such that their combined capacitance is 1.5C. How are they connected?

• A

• B

• C

• D

A parallel plate capacitor is connected to a cell of negligible internal resistance.

The energy stored in the capacitor is 4 J and the electric field in between the plates is 100 N C–1. The distance between the plates of the capacitor is doubled. What are the energy stored and the electric field strength?

• A

• B

• C

• D

Capacitance of a capacitor is defined as the:

• ability to store electrical charge.

• ratio of charge stored to potential difference.

• ratio of potential difference to charge stored.

• ratio of work done to charged stored.

The capacitance of a device is defined as the:

• charge stored by the device.

• energy stored by the device.

• charge stored by the device for a potential difference of 1V across the device.

• energy stored by the device for a potential difference of 1V across the device.

A parallel-plate capacitor is connected to a battery. What happens when a sheet of dielectric material is inserted between the plates without disconnecting the battery?

• The capacitance is unchanged.

• The charge stored decreases.

• The energy stored increases.

• The potential difference between the plates decreases.