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NEET Previous Year Questions (2014-2025): Moving Charges & Magnetism

2025

Q1: A model for the quantized motion of an electron in a uniform magnetic field B states that the flux passing through the orbit of the electron is n (h/e) where n is an integer, h is Planck's constant and e is the magnitude of the electron's charge. According to the model, the magnetic moment of an electron is its lowest energy state will be (m is the mass of the electron):     (NEET 2025)
(a) 2025
(b) 2025
(c) 2025
(d) 2025

Q2: An electron (mass 9 × 10-31 kg and charge 1.6 × 10-19C) moving with speed c/100 (c=speed of light) is injected into a magnetic field 2025of magnitude 9 × 10-4 perpendicular to its direction of motion. We wish to apply an uniform electric field 2025 together with the magnetic field so that the electron does not deflect from its path. Then (speed of light c = 3 × 108 ms-1)     (NEET 2025)
(a) 2025 
(b) 2025
(c) 2025
(d) 2025

Q3: A 2 amp current is flowing through two different small circular copper coils having radii ratio 1 : 2. The ratio of their respective magnetic moments will be:     (NEET 2025)
(a) 2 : 1
(b) 4 : 1
(c) 1 : 4
(d) 1 : 2

2024

Q1: A tightly wound 100 turns coil of radius  10cm carries a current of  7A. The magnitude of the magnetic field at the centre of the coil is (Take permeability of free space as 4π × 10-7SI units):
(a) 44 mT
(b) 4.4 T
(c) 4.4 mT
(d) 44 T               (NEET 2024)

Q2: A sheet is placed on a horizontal surface in front of a strong magnetic pole. A force is needed to:        (NEET 2024)
A. hold the sheet there if it is magnetic.
B. hold the sheet there if it is non-magnetic.
C. move the sheet away from the pole with uniform velocity if it is conducting.
D. move the sheet away from the pole with uniform velocity if it is both, non-conducting and non-polar.
Choose the correct statement(s) from the options given below:
(a) B and D only
(b) A and C only
(c) A, C and D only
(d) C only      [2024]

2023

Q1: A long straight wire of length 2 m and mass 250 g is suspended horizontally in a uniform horizontal magnetic field of  0.7 T. The amount of current flowing through the wire will be (g = 9.8 ms-2) (NEET 2023)
(a) 2.45 A
(b) 2.25 A
(c) 2.75 A
(d) 1.75 A


Q2: A uniform electric field and a uniform magnetic field are acting along the same direction in a certain region. If an electron is projected in the region such that its velocity is pointed along the direction of fields, then the electron:       (NEET 2023)
(a) will turn towards right of direction of motion
(b) will turn towards left of direction of motion
(c) speed will decrease
(d) speed will increase

Q3: A very long conducting wire is bent in a semi-circular shape from A to B as shown in the figure. The magnetic field at point P for steady current configuration is given by           (NEET 2023)
2023(a)2023
(b)2023
(c)2023
(d)2023

Q4: A wire carrying a current I along the positive x-axis has length L. It is kept in a magnetic field 2023The magnitude of the magnetic force acting on the wire is (NEET 2023)
(a) 3 lL
(b)√5 lL
(c) 5 lL
(d)√3 lL

2022

Q1: Two very long, straight, parallel conductors A and B carry current of 5 A and 10 A respectively and are at a distance of 10 cm from each other.  The direction of current in two conductors is same. The force acting per unit length between two conductors is :    (NEET 2022) 2022
(a) 1  x 10-4 Nm-1 and is repulsive
(b) 2  x 10-4 Nm-1 and is attractive
(c) 2 x 10-4 Nm-1 and is repulsive
(d) 1 x 10-4 Nm-1 and is attractive

Q2: The magnetic field on the axis of a circular loop of radius 100 cm carrying current I = √2 A, at point 1 m away from the centre of the loop is given by :    (NEET 2022)
(a) 6.28 x 10-4 T
(b) 3.14 x 10-7 T
(c) 6.28 x 10-7 T
(d) 3.14 x 10-4 T

Q3: A long solenoid of radius 1 mm has 100 turns per mm. If 1 A current flows in the solenoid, the magnetic field strength at the center of the solenoid is        (NEET 2022)

(a) 12.56 × 10-2 T
(b) 12.56 × 10-4 T
(c) 6.28 × 10-4 T
(d) 6.28 × 10-2 T

Q4: From Ampere's circuital law for a long straight wire of circular cross-section carrying a steady current, the variation of the magnetic field in the inside and outside region of the wire is     (NEET 2022)
(a) A linearly increasing function of distance up to the boundary of the wire and then linearly decreasing for the outside region. 
(b) A linearly increasing function of distance r up to the boundary of the wire and then decreasing one with 1/r dependence for the outside region. 
(c) A linearly decreasing function of distance up to the boundary of the wire and then a linearly increasing one for the outside region. 
(d) Uniform and remains constant for both regions.              

Q5: Given below are two statements    (NEET 2022)

Statement I: Biot-Savart's law gives us the expression for the magnetic field strength of an infinitesimal current element (Idl) of a current-carrying conductor only.
Statement II: Biot-Savart's law is analogous to Coulomb's inverse square law of charge q, with the former being related to the field produced by a scalar source, Idl while the latter being produced by a vector source, q. In light of the above statements choose the most appropriate answer from the options given below      

(a) Both Statement I and Statement II are incorrect
(b) Statement I is correct and Statement II is incorrect
(c) Statement I is incorrect and Statement II is correct
(d) Both Statement I and Statement II are correct

Q6: A square loop of side 1 m and resistance 1 Ω is placed in a magnetic field of 0.5 T. If the plane of loop is perpendicular to the direction of magnetic field, the magnetic flux through the loop is    (NEET 2022)
(a) 2 weber
(b) 0.5 weber
(c) 1 weber
(d) Zero weber

2021

Q1: Two toroids 1 and 2 have total number of turns 200 and 100 respectively with average radii 40 cm and 20 cm respectively. If they carry same current i, the ratio of the magnetic fields along the two loops is
(a) 1 : 1
(b) 4 : 1
(c) 2 : 1
(d) 1 : 2

Q2: A thick current-carrying cable of radius 'R' carries current 'I' uniformly distributed across its cross-section. The variation of magnetic field B(r) due to the cable with the distance 'r' from the axis of the cable is represented by:      
A:2021

B:2021

C:2021

D:2021

Q3: An infinitely long straight conductor carries a current of 5 A as shown. An electron is moving with a speed of 10m/s parallel to the conductor. The perpendicular distance between the electron and the conductor is 20 cm at an instant. Calculate the magnitude of the force experienced by the electron at that instant.       
2021

(a) 4π× 10-20 N
(b) 8 × 10-20 N

(c) 4 × 10-20 N

(d) 8π× 10-20 N

Q4: Uniform conducting wire of length 12a and resistance 'R' is wound up as a current-carrying coil in the shape of,
(i) an equilateral triangle of side 'a'
(ii) a square of side 'a'
The magnetic dipole moments of the coil in each case respectively are:
     
(a) 3Ia2 and 4Ia2
(b) 4Ia2 and 3Ia2

(c)√3Iaand 3Ia2
(d) 3Ia2 and Ia2

Q9. In the product

2021

What will be the complete expression for 2021 ?      
(a)2021

B:2021

(c)2021

(d)2021

2020


Q1: A long solenoid of 50 cm in length having 100 turns carries a current of 2.5 A. The magnetic field at the center of the solenoid is : (μ0 = 4π × 10-7 Tm A-1)  
(a) 6.28×10-5 T
(b) 3.14×10-5 T
(c) 6.28×10-4 T
(d) 3.14×10-4 T

2019

Q1: A straight conductor carrying current i splits into two parts as shown in the figure. The radius of the circular loop is R. The total magnetic field at the centre P at the loop is

2019

2019

Q2: Ionized hydrogen atoms and? a-particles with the same momenta enter perpendicular to a constant magnetic field, B. The ratio of the radii of their paths will be: 
(a) 2:1
(b) 1:2
(c)4:1
(d) 1:4

Q3: A cylindrical conductor of radius R is carrying a constant current. The plot of the magnitude of the magnetic field. B with the distance d from the center of the conductor, is correctly represented by the figure :
(a)2019
(b)2019
(c) 2019
(d)2019

2018

Q1: A metallic rod of mass per unit length 0.5 kgm-1 is lying horizontally on a smooth inclined plane which makes an angle of 30° with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction 0.25 T is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is-  
(a) 14.76 A
(b) 5.98 A
(c) 7.14 A
(d) 11.32 A

2017

Q1: A 250-turn rectangular coil of length 2.1 cm and width 1.25 cm carries a current of 85 µA and is subjected to a magnetic field of strength 0.85 T. Work done for rotating the coil by 180º against the torque is:
(a) 4.55 µJ
(b) 2.3 µJ
(c) 1.15 µJ
(d) 9.1 µJ
Q2: An arrangement of three parallel straight wires placed perpendicular to the plane of paper carrying the same current 'I' along the same direction is shown in Fig. The magnitude of force per unit length on the middle wire 'B' is given by:

2017
A:

2017
B:

2017
C:

2017
D:

2017

2016

Q1: A long straight wire of radius a carries a steady current I. The current is uniformly distributed over its cross-section. The ratio of the magnetic fields B and B ′ at radial distances a /2 and 2a respectively, from the axis of the wire is
(a) 1/2
(b) 1
(c) 4
(d) 1/4
Q2: A long wire carrying a steady current is bent into a circular loop of one turn. The magnetic field at the centre of the loop is B. It is then bent into a circular coil of n turns. The magnetic field at the centre of this coil of n turns will be
(a) nB
(b) n2B
(c) 2nB
(d) 2n2B
Q3: A square loop ABCD carrying a current i, is placed near and coplanar with a long straight conductor XY carrying a current I, the net force on the loop will be

(a) 2016

(b) 2016

(c) 2016

(d) 2016

Q4: A long straight wire of radius a carries a steady current I. The current is uniformly distributed over its cross-section. The ratio of the magnetic fields B and B`, at radial distances a/2 and 2a respectively, from the axis of the wire is:   
(a) 4
(b) 1/4
(c) 1/2
(d) 1

2015

Q1: An electron moving in a circular orbit of radius r makes n rotations per second. The magnetic field produced at the centre has magnitude
(a) 2015
(b) Zero
(c) 2015
(d) 2015
Q2: An electron is moving in a circular path under the influence of a transverse magnetic field of 3. 57 × 10-2 T. If the value of e/m is 1.76 × 1011 C/kg, the frequency of revolution of the electron is
(a) 1 GHz
(b) 100 MHz
(c) 62.8 MHz
(d) 6.28 MHz

The document NEET Previous Year Questions (2014-2025): Moving Charges & Magnetism is a part of the NEET Course Physics Class 12.
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FAQs on NEET Previous Year Questions (2014-2025): Moving Charges & Magnetism

1. How do I solve moving charges problems with magnetic force in NEET Physics?
Ans. Use the Lorentz force equation F = qvB sin(θ) to find magnetic force on charged particles. Identify the charge, velocity, and magnetic field direction, then apply the right-hand rule for force direction. Practice previous year NEET questions to recognise common charge motion patterns in uniform and non-uniform magnetic fields.
2. What's the difference between circular and helical motion of charged particles in a magnetic field?
Ans. Circular motion occurs when velocity is perpendicular to the magnetic field; the charged particle moves in a complete circle with constant speed. Helical motion happens when velocity has components both parallel and perpendicular to the field-the particle spirals along field lines. Understanding this distinction is crucial for NEET magnetism problems involving particle trajectories.
3. Why do I keep getting the direction of magnetic force wrong on moving charges?
Ans. The Fleming's left-hand rule is the culprit-use thumb for force, index for field, and middle finger for current direction. For moving charges specifically, always point your fingers in the velocity direction, not current direction. Most NEET exam mistakes occur from mixing this up; practise repeatedly until it becomes automatic.
4. How does the cyclotron frequency formula work for particles moving in magnetic fields?
Ans. Cyclotron frequency (f = qB/2πm) tells how many times per second a charged particle completes one circular orbit. The frequency depends only on charge, magnetic field strength, and mass-not on velocity. This principle explains cyclotron operation and appears frequently in NEET previous year questions on particle acceleration.
5. What should I focus on for magnetic force on current-carrying wires in NEET exams?
Ans. Memorise F = BIL sin(θ) for straight wires and F = BIa for rectangular loops in uniform fields. For torque on current loops: τ = NIAB sin(θ). NEET papers heavily test torque direction using the right-hand rule and force calculations in combined electric-magnetic field scenarios. Refer to mind maps and MCQ tests to strengthen conceptual clarity.
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