Section 7.4 - Capacitance

Question 1

How is capacitance calculated?

Answer 1

C = Q \ V
C = Capacitance (F)
Q = Charge in the plates (C )
V = potential difference across the plates (V)

Question 2

What is the relative permittivity (a.k.a. dielectric constant)?

Answer 2

● The ratio of the charge stored with the dielectric between the plates to the charge stored when the dielectric is not present.
● εr = Q / Q0
● The greater the relative permittivity, the greater the capacitance of the capacitor.

Question 3

What does the area under the graph of
charge against pd represent

Answer 3

The energy stored by the capacitor.

Question 4

Describe the Q against t graph for the discharging of a capacitor through a resistor.

Answer 4

Insert Graph

Question 5

Describe the V against t graph for the discharging of a capacitor through a
resistor.

Answer 5

Insert Graph