Chapter Exam

Chapter 3: Magnetism and Magnetic Effects of Electric Current — Online MCQ Test

Q: Which law gives the magnetic field produced by a small current element?

Answer: B. Biot-Savart law — Biot-Savart law is used to calculate the magnetic field due to a current-carrying conductor element.

Q: The SI unit of magnetic field is

Answer: A. tesla — The tesla (T) is the SI unit of magnetic flux density or magnetic field.

Q: For a long straight current-carrying conductor, the magnetic field lines are

Answer: B. concentric circles around the wire — The magnetic field around a long straight wire forms concentric circles centered on the wire.

Q: The radius of the path of a charged particle in a cyclotron depends on

Answer: C. velocity of the particle and magnetic field — The radius is given by r = mv/qB, so it depends on velocity, mass, charge, and magnetic field.

Q: In a moving coil galvanometer, the current sensitivity is proportional to

Answer: A. number of turns in the coil — Current sensitivity increases with the number of turns because torque increases with more turns.

PHYSICS · CLASS 12th · Tamil Nadu State Board

Practice Chapter 3: Magnetism and Magnetic Effects of Electric Current with a free chapter-wise online MCQ test for Tamil Nadu State Board CLASS 12th PHYSICS. This chapter covers: This chapter details magnetic properties Biot-Savart law and Ampere circuital law. Students explore moving coil galvanometers magnetic field calculations cyclotron mechanics and ea.... AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter 3: Magnetism and Magnetic Effects of Electric Current — Important Questions & Answers (FAQ)

Frequently asked questions from Tamil Nadu State Board CLASS 12th PHYSICS — Chapter 3: Magnetism and Magnetic Effects of Electric Current, with answers and explanations. These are sample questions; the exam has its own separate question set.

Which law gives the magnetic field produced by a small current element?

A. Coulomb's law
B. Biot-Savart law ✓
C. Faraday's law
D. Lenz's law

Answer: B. Biot-Savart law
Biot-Savart law is used to calculate the magnetic field due to a current-carrying conductor element.

The SI unit of magnetic field is

A. tesla ✓
B. weber
C. ampere
D. newton

Answer: A. tesla
The tesla (T) is the SI unit of magnetic flux density or magnetic field.

For a long straight current-carrying conductor, the magnetic field lines are

A. straight lines parallel to the wire
B. concentric circles around the wire ✓
C. radial lines outward from the wire
D. elliptical paths around the wire

Answer: B. concentric circles around the wire
The magnetic field around a long straight wire forms concentric circles centered on the wire.

The radius of the path of a charged particle in a cyclotron depends on

A. only the charge of the particle
B. only the magnetic field
C. velocity of the particle and magnetic field ✓
D. time period of the particle only

Answer: C. velocity of the particle and magnetic field
The radius is given by r = mv/qB, so it depends on velocity, mass, charge, and magnetic field.

In a moving coil galvanometer, the current sensitivity is proportional to