NCERT Class 12 Physics Chapter 4 Moving Charges and Magnetism MCQs & PYQ

1.

Which of the following graphs correctly represents the variation of the magnitude of the magnetic field outside a straight infinite current carrying wire of radius ‘a’, as a function of distance ‘r’ from the centre of  the wire?

(a) (b) (c) (d)

2.

An isosceles right angled current carrying loop PQR is placed in a uniform magnetic field pointing along PR. If the magnetic force acting on the arm PQ is F, then the magnetic force which acts on the arm QR will be

(a) F (b) (c) (d) –F

3.

An electron enters a uniform magnetic field with speed v. It describes a semicircular path and comes out of the field. The final speed of the electron is:

(a) Zero (b) v (c) (d) 2v

4.

A region has a uniform magnetic field in it. A proton enters into the region with velocity making an angle of 45˚with the direction of the magnetic field. In this region the proton will move on a path having the shape of a

(a) straight line (b) circle (c) spiral (d) helix

1.

Write the expression for the Lorentz force on a particle of charge q moving with a velocity in a magnetic field When is the magnitude of this force maximum? Show that no work is done by this force on the particle during its motion from a point to point

(CBSE 2023, 2M)

2.

A long straight wire AB carries a current I. A particle (mass m and charge q) moves with a velocity, parallel to the wire, at a distance d from it as shown in the figure. Obtain the expression for the force experienced by the particle and mention its directions.

(CBSE 2023, 2M)

3.

A long straight conductor kept along X' X axis, carries a steady current I along + x direction. At an instant t, a particle of mass m and charge q at point (x, y) moves with a velocity along + y direction. Find the magnitude and direction of the force on the particle due to the conductor.

(CBSE 2023, 2M)

4.

An alpha particle is projected with velocity into a region in which magnetic field exists. Calculate the acceleration of the particle in the region. and are unit vectors along x, y and z axis respectively and charge to mass ratio for alpha particle is 4·8 × 107 C/kg.

(CBSE 2023, 2M)

Chapter Name

Sub Topics of Chapter 4: Moving Charges and Magnetism

Moving Charges and Magnetism

4.1 Magnetic Force

4.2 Motion in a Magnetic Field

4.3 Motion in Combined Electric and Magnetic Fields

4.4 Magnetic Field Due to a Current Element—Biot-Savart Law

4.5 Magnetic Field on the Axis of a Circular Current Loop

4.6 Ampere’s Circuital Law

4.7 Solenoid and Toroid

4.8 Force Between Two Parallel Currents

4.9 Torque on Current Loop—Magnetic Dipole