PHY2049 - GENERAL PHYSICS II
PRACTICE QUIZ 28

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 28, "Magnetic Induction". This includes questions on magnetic flux, induced emf's and Faraday's Law, Lenz's Law, motional emf, inductance and R-L circuits. 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 3.0 cm by 5.0 cm rectangular coil has 100 turns. Its axis makes an angle of 55° with a uniform magnetic field of 0.35 T. What is the magnetic flux through this coil?

3.0 × 10-4 Wb
4.3 × 10-4 Wb
3.0 × 10-2 Wb
4.3 × 10-2 Wb
5.3 × 10-2 Wb

Q2:

A bar magnet is dropped through a loop of copper wire as shown above. If the positive direction of the induced current I in the loop is as shown by the arrows on the loop, the variation of I with time as the bar magnet falls through the loop is illustrated qualitatively by which of the following graphs? (The time when the midpoint of the magnet passes through the loop is indicated by C.)



1
2
3
4
5


Q3: A loop with a resistance of 2.0 ohm is pushed to the left at a constant speed of 4.0 m/s by a 32 N force. At the instant shown in the figure, the loop is partially in and partially out of a uniform magnetic field. An induced current flows from left to right through the resistor. The length and width of the loop are 2.0 m and 1.0 m, respectively.

What is the magnitude of the induced emf in the loop?

2.0 V
4.0 V
8.0 V
12 V
16 V


Q4: A 0.10 m long solenoid has a radius of 0.05 m and 1.5 × 104 turns. The current in the solenoid changes at a rate of 6.0 A/s. A conducting loop of radius 0.02 m is placed at the center of the solenoid with its axis the same as that of the solenoid as shown.

What is the mutual inductance of this combination?

1.8 × 10-4 H
2.4 × 10-4 H
3.6 × 10-4 H
4.4 × 10-4 H
5.9 × 10-4 H


Q5: An open switch in an R-L circuit is closed at time t = 0, as shown below.

The curve that best illustrates the variation of potential difference across the resistor as a function of time is

1
2
3
4
5


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