Energy stored by capacitors
Question 110S: Short Answer		

1.    A 50 microfarad (mF) capacitor is charged to a p.d. of 60 V.  Calculate the charge on the capacitor.

2.	Calculate the energy stored.

3.	Calculate the energy stored when the p.d. is doubled to 120 V.

4.	Compare your answers to questions 2 and 3. What does this tell you about the relationship between the energy stored by a capacitor and the p.d. to which it has been charged?

Capacitance	Charge	Potential difference	Energy	
1000 mF		16 V		
10 mF	0.01 C			
1.0 F			100 J	
	2.0 mC	5000 V		
		100 V	50 mJ	
33 000 mF			2.0 J	
5.	A 1000 mF capacitor is charged so that its stores 2.0 J of energy. Calculate the p.d. to which it has been charged.

6.	This incomplete table contains values of capacitance, charge, p.d. and energy for a series of charged capacitors. Carry out calculations and fill in the blanks in the table.

7.	A 1.0 mF capacitor is charged to a p.d. of 10 V.  Calculate the charge on the capacitor.

8.	How much charge flowed through the battery during charging?

9.	How many electrons flowed through the battery during charging?

10.	Calculate the energy stored by the capacitor.

11.	How much energy was transferred from the battery during the charging process?

12.	(Rather harder) You should have found different answers for questions 10 and 11. Explain this difference.