PHY2044 - PHYSICS FOR ENGINEERS II
PRACTICE TEST FOR CHAPTER 24

Below you will find a set of 5 conceptual and numerical revision questions selected randomly from lots of questions I have put together covering the material in Chapter 24, "Electrostatic Energy and Capacitance". This includes questions on the electrostatic potential energy, capacitance, combinations of capacitors, storage of electrical energy and dielectrics. When you have finished the quiz, click on the "Submit Quiz" button at the bottom and within seconds it will be automatically graded and the results returned to you!

To select a new set of questions click on the "Reload" or "Refresh" button on your browser. You may find some of the questions duplicated but that's the nature of a random selection. Try it a few times ... it's not fattening and you may learn something!

Many thanks to Mark Wood for producing the quiz-maker code.


Q1: A coaxial cable consists of a wire of radius 0.30 mm and an outer conducting shell of radius 1.0 mm. Its capacitance per unit length is approximately

17 nF/m
0.11 nF/m
92 pF/m
23 pF/m
46 pF/m

Q2: You connect three capacitors as shown in the diagram below.

If the potential difference between A and B is 24.5 V, what is the total energy stored in this system of capacitors if C1 = 5.0 μF, C2 = 4.0 μF and C3 = 3.0 μF?

1.7 × 10-4 J
1.5 × 10-4 J
2.2 × 10-5 J
6.8 × 10-4 J
4.0 × 10-4 J


Q3: What is the equivalent capacitance of the combination of capacitors shown in the circuit?



0.37 μF
3.3 μF
4.6 μF
0.67 μF
2.1 μF


Q4: Q: A capacitor is connected to a battery as shown below.

When a dielectric is inserted between the plates of the capacitor,

only the capacitance changes.
only the voltage across the capacitor changes.
only the charge on the capacitor changes.
both the capacitance and the voltage change.
both the capacitance and the charge change.


Q5: Two identical capacitors A and B are connected across a battery, as shown below.

If mica (κ = 5.4) is inserted in B,

both capacitors will retain the same charge.
B will have the larger charge.
A will have the larger charge.
the potential difference across B will increase.
the potential difference across A will increase.


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