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 27, "Sources of the Magnetic Field". This includes questions on the magnetic field due to moving charges and currents, the Biot-Savart Law and Ampère's Law. 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:

At the instant the negatively charged body is at the origin, the magnetic field at point P due to the motion of this charged body is in the negative x-direction. The charged body must be moving

in the negative z-direction.
in the positive y-direction.
in the positive x-direction.
in the negative y-direction.
in the positive z-direction.

---

Q2: A wire of radius 0.35 cm carries a current of 75 A that is uniformly distributed over its cross-sectional area. The magnetic field 0.20 cm from the center of the wire is approximately

2.5 mT
8.8 μT
3.8 mT
15 mT
2.9 μT

---

Q3: The tightly wound toroid shown below consists of 100 turns of wire, each carrying a current I = 3 A.

If the inner radius a = 12 cm and the outer radius b = 15 cm, the magnetic field at a radius r = 10 cm, due to the current in this toroid, is

462 μT
533 μT
620 μT
zero
280 μT

---

Q4: The drawing shows two long, thin wires that carry currents in the positive z direction. Both wires are parallel to the z axis. The wire carrying 50 A is in the x-z plane and is 5 m from thez axis. The wire carrying 40 A is in the y-z plane and is 4 m from the z axis. What is the magnitude of the magnetic field at the origin?

zero
1.6 × 10^-6 T.
2.8 × 10^-6 T.
3.2 × 10^-6 T.
4.0 × 10^-6 T.

---

Q5: A long, straight wire is carrying a current of 5 A in the direction shown in the figure. The point P is 0.04 m from the wire. What is the magnitude of the magnetic field at the point P?

1.3 × 10^-5 T.
1.9 × 10^-5 T.
2.5 × 10^-5 T.
7.9 × 10^-5 T.
9.4 × 10^-5 T.

---

Click on the Submit Quiz button below to have your quiz automatically graded.

Please note that you may be able to use the "Back" and "Forward" buttons on your browser to check the answers with the questions.