Capacitors

Question 1

What is capacitance?

Answer 1

The charge stored by a capacitor per unit potential difference.

Question 2

What is formed when a capacitor is connected to a power source?

Answer 2

A uniform electric field

Question 3

How do you find the relative permittivity / dielectric constant?

Answer 3

Find the ratio of the permittivity of the dielectric to the permittivity of free space.

Question 4

How does adding a dielectric improve a capacitor?

Answer 4

Polar molecules within the dielectric align with the electric field, such that the positive side of the molecule moves towards the negative plate of the capacitor.

Question 5

What value is the area of a VQ graph?

Answer 5

Energy

Question 6

What stays constant for a connected capacitor?

Answer 6

The terminal pd

Question 7

What stays constant for a disconnected capacitor?

Answer 7

Charge, as it has nowhere to go.

Question 8

What happens if the plate separation is doubled for a connected capacitor?

Answer 8

V is the same
Q halves
C halves
Energy halves

Question 9

What happens if the plate separation is doubled for a disconnected capacitor?

Answer 9

V doubles
Q is the same
C halves
Energy doubles

Question 10

What are the graph shapes for capacitor discharge?

Answer 10

Q/t - inverse proportion
I/t - inverse proportion

Question 11

What are the graph shapes for capacitor charging?

Answer 11

Q/t - curved increase
Vc/t - curved increase
Vr/t - inverse proportion
I/t - inverse proportion