Karnataka 2nd PUC Physics Chapter 4 Important Questions: Moving Charges and Magnetism
Neha Tanna18 Sept, 2026
Karnataka 2nd PUC Physics Chapter 4, Moving Charges and Magnetism, deals with magnetic fields produced by moving charges and current-carrying conductors, magnetic force, Lorentz force and the motion of charged particles in magnetic fields.
Practising questions from these concepts helps students revise formulas and apply them to conceptual and numerical problems. The questions below can be used for chapter-wise revision along with the prescribed textbook and syllabus.
Karnataka 2nd PUC Physics Chapter 4, Moving Charges and Magnetism, deals with magnetic fields produced by moving charges and current-carrying conductors, magnetic force, Lorentz force and the motion of charged particles in magnetic fields.
Practising questions from these concepts helps students revise formulas and apply them to conceptual and numerical problems. The questions below can be used for chapter-wise revision along with the prescribed textbook and syllabus.
Karnataka 2nd PUC Physics Chapter 4 Important Questions
The following questions cover concepts such as magnetic fields, magnetic force, Lorentz force, charged particle motion and force on current-carrying conductors.
1. When a magnetic compass needle is placed near a straight wire carrying current, then
(I) the straight wire causes a noticeable deflection in the compass needle.
(II) the alignment of the needle is tangential to an imaginary circle with the straight wire as its centre and has a plane perpendicular to the wire
(A) (I) is correct
(B) (II) is correct
(C) both (I) and (II) are correct
(D) neither (I) nor (II) is correct
2. A strong magnetic field is applied to a stationary electron. Then the electron
(A) moves in the direction of the field.
(B) remains stationary.
(C) moves perpendicular to the direction of the field.
(D) moves opposite to the direction of the field.
3. What is the work done by a magnetic force on a charged particle (q) moving in a uniform magnetic field (B⃗) with velocity (v⃗)?
(A) qvB
(B) qvB²
(C) Zero
(D) Infinity
4. Which of the following particles will experience the maximum magnetic force when projected with the same velocity perpendicular to a uniform magnetic field?
(A) Alpha particle
(B) Proton
(C) Electron
(D) Neutron
5. A positive charge enters a magnetic field and travels antiparallel to the field. It experiences
(A) an upward force.
(B) a downward force.
(C) a constant force.
(D) no force.
6. Assertion: A magnetic field interacts with a moving charge and not with a stationary charge.
Reason: A moving charge produces a magnetic field.
(A) Both assertion and reason are true, and reason is the correct explanation of assertion.
(B) Both assertion and reason are true, but reason is not the correct explanation of assertion.
(C) Assertion is true, but reason is false.
(D) Both assertion and reason are false.
7. A positive charge q enters a uniform magnetic field B⃗ at an angle θ (where 0° < θ < 180°) with the magnetic field. Which graph best shows the variation in the magnitude of the magnetic force F⃗ with θ?
8. The correct expression for the Lorentz force (F⃗) acting on a particle with charge (q) moving with a velocity (v⃗) in a region containing both an electric field (E⃗) and a magnetic field (B⃗) is?
9. In a certain region of space, the electric field and magnetic field are perpendicular to each other. An electron enters perpendicularly to both the fields and moves undeflected. The velocity of the electron is?
10. The correct vector expression for the magnetic force (F⃗) experienced by a straight conductor of length (L) carrying a current (I) in a uniform magnetic field (B⃗) is
11. A straight wire of length 0.5 m carries a current of 2.0 A. It is placed in a uniform magnetic field of 0.3 T such that it is perpendicular to the field lines. What is the magnitude of the force acting on the wire?
(A) 0.15 N
(B) 0.6 N
(C) 0.3 N
(D) 0 N
12. If the current flowing through a conductor placed in a uniform magnetic field is doubled, and its length inside the field is halved, how does the magnetic force on the conductor change?
(A) It becomes four times the original force
(B) It is halved
(C) It remains the same
(D) It is doubled
13. If you double the velocity of a charged particle moving perpendicular to a uniform magnetic field, the radius of its circular path will:
(A) Remain the same
(B) Be halved
(C) Double
(D) Quadruple
14. An electron (e-), a proton (p), and an alpha particle (α) enter a uniform magnetic field perpendicularly with the same parameter. Match the parameter with the correct comparison of their radii.
|
Column I (Constant Parameter) |
Column II (Radius Comparison) |
|
(a) Same velocity (v⃗)(\vec v) |
(1) rα<rp=rer_\alpha < r_p = r_e |
|
(b) Same momentum (p⃗)(\vec p) |
(2) re<rp=rαr_e < r_p = r_\alpha |
|
(c) Same kinetic energy (K)(K) |
(3) re<rp<rαr_e < r_p < r_\alpha |
(A) (a) – (3), (b) – (1), (c) – (2)
(B) (a) – (1), (b) – (2), (c) – (3)
(C) (a) – (2), (b) – (3), (c) – (1)
(D) (a) – (3), (b) – (2), (c) – (1)
15. A charge moves in a circle perpendicular to a magnetic field. Upon which of the following does the time period of revolution not depend?
(A) Magnetic field
(B) Charge
(C) Mass of the particle
(D) Velocity of the particle
16. The horizontal component of Earth's magnetic field at a certain place is 3.0 x 10-5 T and has a direction from the geographic south to the geographic north. The force per unit length on a very long straight conductor carrying a steady current of 1.2 A in the east-to-west direction is:
(A) 3.0 × 10-5 Nm-1
(B) 3.6 × 10-5 Nm-1
(C) 3.2 × 10-5 Nm-1
(D) 3.8 × 10-5 Nm-1
17. An electron of energy 1800 eV describes a circular path in a magnetic field with a flux density 0.4 T. The radius of path is (q = 1.6 × 10-19 C, m = 9.1 × 10-31 kg)
(A) 2.58 × 10-4 m
(B) 2.58 × 10-3 m
(C) 3.58 × 10-4 m
(D) 3.58 × 10-3 m
18. Match the condition of entry of a charged particle into a uniform magnetic field with the resulting shape of its trajectory.
|
Column I (Condition) |
Column II (Shape of the Trajectory) |
|
(a) Velocity v⃗\vec v is parallel to B⃗\vec B (θ=0∘)(\theta = 0^\circ) |
(2) Straight line path |
|
(b) Velocity v⃗\vec v is perpendicular to B⃗\vec B (θ=90∘)(\theta = 90^\circ) |
(3) Circular path |
|
(c) Velocity v⃗\vec v is at an acute angle to B⃗\vec B (θ<90∘)(\theta < 90^\circ) |
(1) Helical path with uniform pitch |
(A) (a) – (3), (b) – (2), (c) – (1)
(B) (a) – (2), (b) – (1), (c) – (3)
(C) (a) – (2), (b) – (3), (c) – (1)
(D) (a) – (1), (b) – (3), (c) – (2)
19. Two charged particles traverse identical helical paths in completely opposite senses in a uniform magnetic field B⃗ = B0 k̂.
(A) They have equal z-components of momentum.
(B) They must have equal charges.
(C) They necessarily represent a particle-antiparticle pair.
(D) The charge-to-mass ratio satisfy: (q/m)1 + (q/m)2 = 0.
20. At what distance from a long straight wire carrying a current of 12 A will the magnetic field be equal to 3 × 10–5 Wb/ m2?
(A) 8 × 10−2m
(B) 12 × 10−2m
(C) 18 × 10−2m
(D) 24 × 10−2m
Karnataka 2nd PUC Physics Chapter 4 Important Questions PDF Download
Students can download the Karnataka 2nd PUC Physics Chapter 4 Important Questions PDF with answers for quick and effective revision.
The questions cover important concepts from Moving Charges and Magnetism, including magnetic force, Lorentz force, charged particle motion, and magnetic fields. Practising these questions can help students strengthen their conceptual understanding, improve problem-solving skills, revise important formulas, and prepare effectively for board and competitive examinations.
Karnataka 2nd PUC Physics Chapter 4 Important Questions
How to use Karnataka 2nd PUC Physics Chapter 4 Important Questions
Students can use these important questions and notes to revise key concepts, practise numerical problems, understand formulas, and identify areas that require additional preparation before the examination.
-
Understand the Concepts
Read each question carefully and revise the related concepts, including magnetic force, Lorentz force, magnetic fields, and motion of charged particles. -
Revise Important Formulas
Make a separate list of important formulas and understand the quantities used in each formula before attempting numerical questions. -
Practise Numerical Questions
Solve numerical-based questions independently first. Compare your calculation with the solution and identify any mistakes in applying formulas or units. -
Focus on Conceptual Questions
Practise assertion-reason, statement-based, and multiple-choice questions regularly to strengthen your understanding of Moving Charges and Magnetism. -
Revise Before the Exam
Use these questions for final revision after completing the chapter. Reattempt difficult questions and review formulas and concepts before the examination.
Related Sources:
PW provides Karnataka 2nd PUC exam content, including Karnataka Board Exam Blogs, sample papers, mock tests, guidance sessions, and more. Also, enroll today in Karnataka 2nd PUC Online Coaching to prepare.
FAQs
What is Karnataka 2nd PUC Physics Chapter 4 about?
How can students prepare Chapter 4 using important questions?
Are important questions useful for board and competitive exam preparation?
