Magnetic Effects of Current Practice Questions
JEE · Physics · 1559 free MCQs with instant results and detailed explanations.
1559
Total
356
Easy
741
Medium
462
Hard
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Topics in Magnetic Effects of Current
Ampere's Law
351
Solenoid and Toroid
317
Force on Current-Carrying Conductor
248
Moving Coil Galvanometer
298
Biot-Savart Law
345
Sample Questions from Magnetic Effects of Current
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 produced by a static charge
C.
The force between two charges
D.
The potential energy of a magnetic dipole
Show Answer & Explanation
Correct Answer: A
The Biot-Savart law describes how a steady current creates a magnetic field in the surrounding space.
Q2
Easy
If a long straight conductor carries a current I, what is the direction of the magnetic field at a point north of the wire?
A.
Towards the east
B.
Towards the west
C.
Towards the south
D.
Towards the north
Show Answer & Explanation
Correct Answer: A
Using the right-hand rule, if the thumb points in the direction of the current, the curled fingers show the direction of the magnetic field.
Q3
Easy
What is the formula for the magnetic field (B) at a distance r from a straight current-carrying conductor using the Biot-Savart law?
A.
B = (ฮผโ/4ฯ) * (I/r)
B.
B = (ฮผโ/4ฯ) * (I/rยฒ)
C.
B = (ฮผโI/2ฯr)
D.
B = (ฮผโI/4ฯrยฒ)
Show Answer & Explanation
Correct Answer: C
The magnetic field around a long straight wire carrying current is given by B = (ฮผโI/2ฯr).
Q4
Medium
A long straight current-carrying wire produces a magnetic field. If the current in the wire is doubled, how does the magnetic field strength at a distance 'r' from the wire change?
A.
It doubles
B.
It remains the same
C.
It increases four times
D.
It decreases
Show Answer & Explanation
Correct Answer: A
According to the Biot-Savart Law, the magnetic field strength (B) produced by a straight current-carrying wire is directly proportional to the current (I). Hence, if the current is doubled, the magnetic field at distance 'r' also doubles.
Q5
Medium
Using the Biot-Savart Law, what is the direction of the magnetic field produced by a straight wire carrying current, as observed from a point located above the wire?
A.
Towards the wire
B.
Away from the wire
C.
Perpendicular to the wire
D.
In the same direction as the current
Show Answer & Explanation
Correct Answer: C
The direction of the magnetic field due to a straight current-carrying wire can be determined using the right-hand rule. At a point above the wire, the magnetic field lines are perpendicular to the wire and follow a circular path.
Q6
Medium
A circular loop of radius R carries a current I. According to the Biot-Savart Law, what is the magnetic field at the center of the loop?
A.
Zero
B.
(ฮผโI)/(2R)
C.
(ฮผโI)/(4R)
D.
(ฮผโI)/(R)
Show Answer & Explanation
Correct Answer: B
For a circular loop, the magnetic field at the center is given by B = (ฮผโI)/(2R). This is derived from the Biot-Savart Law by integrating the contributions from each infinitesimal segment of the loop.
Q7
Medium
If the radius of a circular loop is halved while keeping the current constant, how does the magnetic field at the center change?
A.
It remains constant
B.
It doubles
C.
It halves
D.
It quadruples
Show Answer & Explanation
Correct Answer: B
Since the magnetic field at the center of the loop is inversely proportional to the radius, halving the radius results in doubling the magnetic field strength.
Q8
Hard
A long straight wire carries a current of 10 A. Calculate the magnetic field at a point 0.1 m away from the wire. (Use ยตโ = 4ฯ ร 10โปโท Tm/A)
A.
2 ร 10โปโต T
B.
5 ร 10โปโถ T
C.
4 ร 10โปโถ T
D.
1 ร 10โปโต T
Show Answer & Explanation
Correct Answer: A
Using the Biot-Savart Law, B = (ยตโ/4ฯ) * (I/r), substituting values gives B = 2 ร 10โปโต T.
Q9
Hard
Two parallel wires are separated by a distance of 0.5 m and carry currents of 5 A and 10 A in the same direction. What is the magnetic field at a point halfway between the wires?
A.
0 T
B.
1 ร 10โปโถ T
C.
2 ร 10โปโถ T
D.
5 ร 10โปโถ T
Show Answer & Explanation
Correct Answer: C
The magnetic fields due to both wires add up at the midpoint since they are in the same direction, resulting in 2 ร 10โปโถ T.
Q10
Hard
A circular loop of radius 0.1 m carries a current of 3 A. What is the magnetic field strength at its center?
A.
1.2 ร 10โปโถ T
B.
6 ร 10โปโถ T
C.
3 ร 10โปโถ T
D.
1.5 ร 10โปโถ T
Show Answer & Explanation
Correct Answer: A
Using the Biot-Savart Law for a circular loop, B = (ยตโ * I)/(2R); substituting gives 1.2 ร 10โปโถ T.
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Magnetic Effects of Current โ JEE Physics Practice Questions Online
This page contains 1559 practice MCQs for the chapter Magnetic Effects of Current in JEE Physics. The questions are organized by difficulty โ 356 easy, 741 medium, 462 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 5 topics, giving you comprehensive coverage of the entire chapter.