Capacitors

Question 1

What is a capacitor?

Answer 1

An electrical component that can store charge.

Question 2

What are capacitors made up of?

Answer 2

Made up of two conducting plates separated by a gap or a dielectric. (Insulator)

Question 3

How is a p.d. created?

Answer 3

When connected to a power source, positive and negative charge builds up on opposite plates. The insulating material prevents the charge moving between the two plates, so a potential difference is created.

Question 4

What exists between the two plates of a charged capacitor?

Answer 4

Uniform electric field.

Question 5

What is capacitance?

Answer 5

Charge per unit voltage.

Question 6

How do you calculate capacitance in series and parallel?

Answer 6

Parallel - C(total) = C1 + C2

Series - 1/C(total) = 1/C1 + 1/C2

Question 7

What are 3 uses of capacitors?

Answer 7

Flash photography, back-up power supplies, smoothing out p.d.

Question 8

What is the time constant?

Answer 8

The time taken for the p.d., charge or current to fall to 37% of the starting value