Capacitance is the charge stored per unit potential difference and it is measured in farads, so this Year 13 sheet opens with the defining statement behind Q = CV. Paralleled capacitors in the key combine by simple addition, and the stored energy appears as ½CV².
Key Takeaways
Capacitance is charge stored per unit potential difference (Q1).
The unit of capacitance is the farad (Q2).
Parallel capacitors add: C = C₁ + C₂, and energy stores as ½CV².
Section A: Multiple Choice Questions (1 Mark Each)
Choose the correct option for each question.
1.Capacitance is the charge stored per
(a) unit potential difference(b) unit current(c) unit resistance(d) unit time
2.The unit of capacitance is the
(a) farad(b) ohm(c) watt(d) henry
3.The charge stored by a capacitor is given by
(a) Q = CV(b) Q = C ÷ V(c) Q = V ÷ C(d) Q = C + V
4.The energy stored in a capacitor is
(a) ½CV²(b) CV(c) ½C²V(d) V ÷ C
5.A capacitor stores energy in
(a) an electric field(b) a magnetic field(c) a gravitational field(d) heat
6.For capacitors connected in parallel, the total capacitance is
(a) the sum of the individual capacitances(b) less than the smallest capacitance(c) the reciprocal sum(d) always equal to one of them
Section B: Short Answer Type Questions (2 Marks Each)
Show all steps clearly.
7.Define capacitance.
8.Write the formula for capacitance.
9.State the unit of capacitance.
10.Write the formula for the energy stored in a capacitor.
11.What happens to the capacitance if the plate separation is increased?
12.What happens to the charge stored if the voltage is doubled?
13.What is the time constant of a charging capacitor?
14.Give one use of a capacitor.
Section C: Numericals & Word Problems (3 Marks Each)
Apply the concepts to solve the problems. Show all working.
15.A capacitor stores 40 µC of charge at a voltage of 8 V. Using C = Q ÷ V, find the capacitance.
16.A 10 µF capacitor is connected to a 12 V supply. Using Q = CV, find the charge stored.
17.A 2 µF capacitor is charged to 6 V. Using E = ½CV², find the energy stored.
18.A capacitor stores 50 µC of charge at a voltage of 10 V. Using C = Q ÷ V, find the capacitance.
19.Two capacitors of 3 µF and 6 µF are connected in parallel. Find the total capacitance.
20.A 4 µF capacitor is charged to 5 V. Using E = ½CV², find the energy stored.
Answer Key
1. a) unit potential difference
2. a) farad
3. a) Q = CV
4. a) ½CV²
5. a) an electric field
6. a) the sum of the individual capacitances
7. Refer to solution guide.
8. Refer to solution guide.
9. Refer to solution guide.
10. Refer to solution guide.
11. Refer to solution guide.
12. Refer to solution guide.
13. Refer to solution guide.
14. Refer to solution guide.
15. Refer to solution guide.
16. Refer to solution guide.
17. Refer to solution guide.
18. Refer to solution guide.
19. Refer to solution guide.
20. Refer to solution guide.
End of Worksheet
People Also Ask
What is capacitance?
The charge stored per unit potential difference, option (a) in this worksheet (Q1).
What is the unit of capacitance?
The farad, option (a) in this worksheet (Q2).
How is energy stored in a capacitor written?
½CV², from the answer key on this page.
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