An electron projected perpendicular to a uniform magnetic field B moves in a circle. If Bohr's quantization is applicable, then the radius of the electronic orbit in the first excited state is :

$\sqrt{\frac{\mathrm{h}}{2 \pi e \mathrm{eB}}}$

Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : An electron in a certain region of uniform magnetic field is moving with constant velocity in a straight line path. Reason (R) : The magnetic field in that region is along the direction of velocity of the electron. In the light of the above statements, choose the correct answer from the options given below :

Both (A) and (R) are true and (R) is the correct explanation of (A)

Both $(\mathbf{A})$ and $(\mathbf{R})$ are true but $(\mathbf{R})$ is NOT the correct explanation of (A)

An electron is projected with uniform velocity along the axis inside a current-carrying long solenoid. Then :

the electron will continue to move with uniform velocity along the axis of the solenoid.

the electron will experience a force at $$45^{\circ}$$ to the axis and execute a helical path.

the electron will be accelerated along the axis.

the electron path will be circular about the axis.

Magnetics — JEE Main Previous Year Questions

207 solved PYQs · 2016–2026 · Mathematics

Solved PYQs: 207
Years covered: 2016–2026
Avg / year: ~19
Subject: Mathematics

How many JEE Main questions come from Magnetics?

Magnetics has contributed 207 questions to Joint Entrance Examination (Main) papers between 2016 and 2026 — an average of about 19 questions a year. That count is measured from EByAi’s bank of 55,289 JEE Main questions, not estimated from a syllabus. Every one of the 207 questions carries a written, step-by-step solution, and each is tagged to Magnetics within Mathematics, so you can drill this chapter across every year at once instead of hunting through paper PDFs. Practising a chapter’s full PYQ history is the fastest way to learn the patterns examiners reuse.

Sample Magnetics questions from real JEE Main papers

These are 5 real questions from the bank — exactly as asked, with the answer one tap away. All 207 Magnetics questions (with full written solutions) are available in practice.

Question 1 · JEE Main 2025
An electron projected perpendicular to a uniform magnetic field B moves in a circle. If Bohr's quantization is applicable, then the radius of the electronic orbit in the first excited state is :
1. (A) $\frac{h}{π e B}$
2. (B) $\frac{4 h}{π e B}$
3. (C) $\frac{h}{2 π e eB}$
4. (D) $\frac{2 h}{π e B}$
Show answerAnswer
$Answer: (A) \frac{h}{π e B}$
Question 2 · JEE Main 2025
Consider a long straight wire of a circular cross-section (radius a ) carrying a steady current I . The current is uniformly distributed across this cross-section. The distances from the centre of the wire’s cross-section at which the magnetic field [inside the wire, outside the wire] is half of the maximum possible magnetic field, anywhere due to the wire, will be :
1. (A) $[ a /2, 3 a ]$
2. (B) $[ a /4, 3 a /2]$
3. (C) $[ a /2, 2 a ]$
4. (D) $[ a /4, 2 a ]$
Show answerAnswer
$Answer: (C) [ a /2, 2 a ]$
Question 3 · JEE Main 2025
Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : An electron in a certain region of uniform magnetic field is moving with constant velocity in a straight line path. Reason (R) : The magnetic field in that region is along the direction of velocity of the electron. In the light of the above statements, choose the correct answer from the options given below :
1. (A) $(A) is true but (R) is false$
2. (B) $Both (A) and (R) are true and (R) is the correct explanation of (A)$
3. (C) $Both (A) and (R) are true but (R) is NOT the correct explanation of (A)$
4. (D) $(A) is false but (R) is true$
Show answerAnswer
$Answer: (B) Both (A) and (R) are true and (R) is the correct explanation of (A)$
Question 4 · JEE Main 2024
An electron is projected with uniform velocity along the axis inside a current-carrying long solenoid. Then :
1. (A) $the electron will experience a force at 4 5^{\circ} to the axis and execute a helical path.$
2. (B) $the electron will be accelerated along the axis.$
3. (C) $the electron path will be circular about the axis.$
4. (D) $the electron will continue to move with uniform velocity along the axis of the solenoid.$
Show answerAnswer
$Answer: (D) the electron will continue to move with uniform velocity along the axis of the solenoid.$
Question 5 · JEE Main 2024
In a coaxial straight cable, the central conductor and the outer conductor carry equal currents in opposite directions. The magnetic field is zero :
1. (A) $inside the outer conductor$
2. (B) $outside the cable$
3. (C) $in between the two conductors$
4. (D) $inside the inner conductor$
Show answerAnswer
$Answer: (B) outside the cable$

Magnetics questions by year

Year	Questions	Share of chapter questions
2026	19
2025	22
2024	31
2023	30
2022	28
2021	21
2020	21
2019	24
2018	5
2017	3
2016	3

Practise these 207 questions with solutions

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FAQs

How many JEE Main questions have been asked from Magnetics?

EByAi's bank holds 207 real JEE Main questions from Magnetics, asked between 2016 and 2026 — about 19 per year on average. Every count is measured from actual papers, not estimated.

Is Magnetics important for JEE Main?

207 questions over 11 papers make Magnetics a high-weightage chapter in JEE Main Mathematics. The year-wise table above shows exactly how often it appears.

Can I solve Magnetics PYQs online for free?

Yes. EByAi lets you solve JEE Main past-year questions in the browser with written solutions — free daily practice, no card needed.

More JEE Main Mathematics chapters

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