Capacitors

Question 1

What does it mean for a capacitor to have 1 farad(C)?

Answer 1

This means that one coulomb of charge is stored when the potential difference across the capacitor is one volt.

Question 2

What formula can we use for capacitance?

Answer 2

C = Q/V

Question 3

How do we determine the charge stored in a charging capacitor?

Answer 3

Q = It

Question 4

How can we find the total energy stored/work done in a charged capcitor through calculation and graphically?

Answer 4

E = 1/2(QV) = 1/2(CV^2) = 1/2(Q^2/C)
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Area under QV graph

Question 5

Describe the charging curve in terms of voltage in a capacitor

Answer 5

As the capacitor charges, the current decreases proportionally to the amount of current it has left. This is why we see it slow down.

Question 6

Describe the effect of resistance on the on the charging curve.

Answer 6

Increased resistance means increased time for the capacitor to charge, as it reduces the current.

Question 7

Describe the effect of capacitance on the charging curve.

Answer 7

This affects the amount of charge that can be stored, so depending on whether you increase it or decrease it the time taken for the charge to flow will be longer.