Moving Charges and Magnetism Practice Questions

Class 12 · Physics · 1980 free MCQs with instant results and detailed explanations.

1980
Total
685
Easy
970
Medium
325
Hard

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Topics in Moving Charges and Magnetism

Ampere's Law 524
Force on Current-Carrying Conductor 423
Cyclotron 528
Biot-Savart Law 505

Sample Questions from Moving Charges and Magnetism

Here are 10 sample questions. Start a quiz to get randomized questions with scoring.

Q1
Easy
What does the Biot-Savart Law primarily describe?
A. The magnetic field generated by a steady current.
B. The electric field around a charged particle.
C. The motion of charged particles in a magnetic field.
D. The relationship between voltage and current.
Show Answer & Explanation
Correct Answer: A
The Biot-Savart Law describes how a magnetic field is generated in space around a current-carrying conductor.
Q2
Easy
If a long straight conductor carries a current of 5 A, what will be the magnetic field at a distance of 0.1 m from the conductor? (Use ฮผโ‚€ = 4ฯ€ x 10โปโท T m/A)
A. 1.0 x 10โปโถ T
B. 2.0 x 10โปโถ T
C. 5.0 x 10โปโถ T
D. 3.0 x 10โปโถ T
Show Answer & Explanation
Correct Answer: A
Using the Biot-Savart Law, the magnetic field B = (ฮผโ‚€ * I) / (2ฯ€ * r), we find B = (4ฯ€ x 10โปโท * 5) / (2ฯ€ * 0.1) = 1.0 x 10โปโถ T.
Q3
Easy
According to the Biot-Savart Law, which of the following factors does NOT affect the magnetic field produced by a current-carrying conductor?
A. The amount of current flowing through the conductor.
B. The distance from the conductor to the point where the field is measured.
C. The length of the conductor.
D. The medium surrounding the conductor.
Show Answer & Explanation
Correct Answer: C
The length of the conductor does not affect the magnetic field strength at a point far away; it is primarily determined by current and distance.
Q4
Medium
What is the direction of the magnetic field produced by a long straight conductor carrying current?
A. Along the direction of current
B. Perpendicular to the current
C. Opposite to the direction of current
D. Along the axis of the conductor
Show Answer & Explanation
Correct Answer: B
The magnetic field produced by a long straight conductor is always perpendicular to the direction of the current, following the right-hand rule.
Q5
Medium
A circular loop of radius 'r' carries a current 'I'. What is the magnetic field at the center of the loop?
A. 0
B. ฮผโ‚€ I / 2r
C. ฮผโ‚€ I / r
D. ฮผโ‚€ I / (4ฯ€r)
Show Answer & Explanation
Correct Answer: C
The magnetic field at the center of a circular loop carrying current is given by B = ฮผโ‚€ I / (4ฯ€r), but for the center of the loop, it simplifies to ฮผโ‚€ I / r.
Q6
Medium
If the current in a wire is doubled, how does the magnetic field around it change?
A. Remains constant
B. Doubles
C. Halves
D. Increases by a factor of four
Show Answer & Explanation
Correct Answer: B
According to Biot-Savart Law, the magnetic field produced by a current-carrying wire is directly proportional to the current.
Q7
Medium
Which of the following configurations will produce no magnetic field at the center?
A. Single circular loop
B. Two parallel wires carrying current in the same direction
C. Two parallel wires carrying current in opposite directions
D. A solenoid
Show Answer & Explanation
Correct Answer: C
When two parallel wires carry current in opposite directions, the magnetic fields produced cancel each other out at the center.
Q8
Hard
A circular loop of radius R carries a current I. What is the magnetic field strength at the center of the loop?
A. ฮผโ‚€I/(2R)
B. ฮผโ‚€I/R
C. ฮผโ‚€I/(4ฯ€R)
D. ฮผโ‚€I/(2ฯ€R)
Show Answer & Explanation
Correct Answer: D
The magnetic field at the center of a circular loop is given by B = ฮผโ‚€I/(2R). However, it is important to remember that the magnetic field strength at the center is expressed as ฮผโ‚€I/(2ฯ€R) when considering the entire circular path.
Q9
Hard
A straight conductor carrying current I is placed in a uniform magnetic field B. If the conductor is at an angle ฮธ with respect to the magnetic field, which of the following represents the force experienced by the conductor?
A. F = IBL
B. F = IBL sin(ฮธ)
C. F = IBL cos(ฮธ)
D. F = IBL tan(ฮธ)
Show Answer & Explanation
Correct Answer: B
The force experienced by a current-carrying conductor in a magnetic field is given by F = IBL sin(ฮธ), where ฮธ is the angle between the direction of the magnetic field and the current.
Q10
Hard
Two long parallel wires are separated by a distance d and carry currents Iโ‚ and Iโ‚‚ in the same direction. What is the expression for the net magnetic field at a point midway between the wires?
A. B = 0
B. B = (ฮผโ‚€/2ฯ€)(Iโ‚ + Iโ‚‚)/d
C. B = (ฮผโ‚€/2ฯ€)(Iโ‚ - Iโ‚‚)/d
D. B = (ฮผโ‚€/4ฯ€)(Iโ‚ + Iโ‚‚)/dยฒ
Show Answer & Explanation
Correct Answer: B
At a point midway between two parallel wires carrying currents in the same direction, the magnetic fields due to each wire add up. The net magnetic field at that point is given by B = (ฮผโ‚€/2ฯ€)(Iโ‚ + Iโ‚‚)/d.

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Moving Charges and Magnetism โ€” Class 12 Physics Practice Questions Online

This page contains 1980 practice MCQs for the chapter Moving Charges and Magnetism in Class 12 Physics. The questions are organized by difficulty โ€” 685 easy, 970 medium, 325 hard โ€” so you can choose the right level for your preparation.

Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit. This chapter covers 4 topics, giving you comprehensive coverage of the entire chapter.