Module 6 - 6.1.3 Charging and Discharging Capacitors

Question 1

The rate at which charge moves onto the plates is

Answer 1

not linear

Question 2

Charging: current is max at (3)

Answer 2

• instant capacitor starts to charge
• gradually decreases until it reaches zero
• at this point capacitor is fully charged

Question 3

Charging: Equations (3)

Answer 3

Q=Qf(1-e^(-t/CR))
V=Vf(1-e^(-t/CR))
I=I0(e^(-t/CR))

Question 4

Discharging: current is max at (3)

Answer 4

• instant capacitor starts to discharge
• gradually decreases until it reaches zero
• at this point capacitor is fully discharged

Question 5

Discharging: Equations (3)

Answer 5

Q=Q0(e^(-t/CR))
V=V0(e^(-t/CR))
I=I0(e^(-t/CR))

Question 6

The time constant of a capacitor circuit is the

Answer 6

time taken for the charge on the capacitor to fall to 1/e of its original maximum value

Question 7

𝜀 =

Answer 7

𝜀0 x 𝜀r

Question 8

It is - for charge to get onto the plates at first but

Answer 8

easier
becomes more difficult as the charge on the plates increases

Question 9

The greater the size of the resistance in the circuit (2)

Answer 9

• The longer it will take for a capacitor to become fully charged/discharged
• Does not affect the final values of the pd, charge and energy stored