List of top Physics Questions on Moving Charges and Magnetism asked in CBSE CLASS XII

A 1 cm straight segment of a conductor carrying 1 A current in \( x \)-direction lies symmetrically at the origin of Cartesian coordinate system. The magnetic field due to this segment at point (1m, 1m, 0) is:
What is the source of force acting on a current-carrying conductor placed in a magnetic field? Obtain the expression for the force acting between two long straight parallel conductors carrying steady currents and hence define Ampère’s law.
Two infinitely long conductors kept along XX' and YY' axes are carrying current \( I_1 \) and \( I_2 \) along -X axis and -Y axis respectively. Find the magnitude and direction of the net magnetic field produced at point P(X, Y).
Write two characteristics of equipotential surfaces. A uniform electric field of 50 NC\(^{-1}\) is set up in a region along the \( x \)-axis. If the potential at the origin \( (0, 0) \) is 220 V, find the potential at a point \( (4m, 3m) \).
A point charge \( q \) is moving with velocity \( \mathbf{v} \) in a uniform magnetic field \( \mathbf{B} \). Find the work done by the magnetic force on the charge.
Find the value of \( v_0 \) in terms of \( E \), \( d \), and \( I \).
What are the various forces acting on the charged particle?
In a region of a uniform electric field \( \mathbf{E} \), a negatively charged particle is moving with a constant velocity \( \mathbf{v} = -v_0 \hat{i} \) near a long straight conductor coinciding with XX' axis and carrying current \( I \) towards -X axis. The particle remains at a distance \( d \) from the conductor.
Obtain an expression for the torque \( \tau \) acting on a current-carrying loop in a uniform magnetic field \( \vec{B} \). Draw the necessary diagram.
Explain the necessary conditions in which the trajectory of a charged particle is helical in a uniform magnetic field.
In a hydrogen atom, the electron moves in an orbit of radius \( 2 \, \text{Å} \) making \( 8 \times 10^{14} \) revolutions per second. Find the magnetic moment associated with the orbital motion of the electron.
A particle of mass \( m \) and charge \( q \) is moving with a velocity \( \vec{v} \) in a magnetic field \( \vec{B} \) as shown in the figure. Show that it follows a helical path. Hence, obtain its frequency of revolution.
charged particle in a magnetic field
 
Two long, straight, parallel conductors carry steady currents in opposite directions. Explain the nature of the force of interaction between them. Obtain an expression for the magnitude of the force between the two conductors. Hence define one ampere.
Assertion (A): An electron and a proton enter with the same momentum \( \vec{p} \) in a magnetic field \( \vec{B} \) such that \( \vec{p} \perp \vec{B} \). Then both describe a circular path of the same radius.
Reason (R): The radius of the circular path described by the charged particle (charge \( q \), mass \( m \)) moving in the magnetic field \( \vec{B} \) is given by \( r = \frac{mv}{qB} \).
A wire of length 4.4 m is bent round in the shape of a circular loop and carries a current of 1.0 A. The magnetic moment of the loop will be: