Worksheet: Capacitor Charging and Discharging

In this worksheet, we will practice calculating instantaneous current, charge, and voltage in circuits containing a resistor and a capacitor.

Q1:

What is the time constant of the circuit shown in the diagram? Answer to three significant figures.

Q2:

A circuit with a resistance of 42 Ω and a capacitance of 540 µF is powered by a 3.4 V battery. How much time after the capacitor starts being charged is the instantaneous current in the circuit 15 mA?

  • A 0.019 s
  • B 0.032 s
  • C 0.038 s
  • D 0.076 s
  • E 0.014 s

Q3:

A resistor–capacitor circuit powered by a 12.6 V battery has a time constant of 177 ms. How much time must the capacitor be charged for to have a potential difference of 9.30 V across it?

Q4:

What is the time constant of a circuit with a resistance of 7.5 kΩ and a capacitance of 450 µF?

Q5:

A resistor–capacitor circuit is powered by a 9.5 V battery. The initially uncharged capacitor is charged for 320 ms, after which the instantaneous potential difference across it is 5.5 V. What is the time constant of the circuit?

Q6:

A resistor–capacitor circuit powered by an 8.20 V battery has a time constant of 156 ms. The initially uncharged capacitor is charged for 215 ms. What is the potential difference across the capacitor after that time?

Q7:

What resistance would be needed in a circuit that contains a 6.75 µF capacitor for the time constant of the circuit to be 0.125 ms?

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.