Chapter 21 - Capacitors

Question 1

What is a capacitor?

Answer 1

Two metallic plates separated by an insulator, where charge is stored.

Question 2

Define capacitance

Answer 2

The charge stored per unit P.D. across a capacitor.

Question 3

What happens in terms of electrons when charging a capacitor?

Answer 3

Electrons build up on one plate (making it negative), and none are left on the other plate (making it positive).

Question 4

What happens in terms of electrons when discharging a capacitor?

Answer 4

Electrons move to the positive plate until they are evenly distributed (P.D. = 0).

Question 5

Give 2 uses of capacitors.

Answer 5

-A camera flash.
-Back-up power supplies in case of a short outage.
-Smoothing out p.d. when converting a.c. to d.c.