NEET Physics Magnetic Effects of Current and Magnetism MCQs

A short bar magnet of magnetic moment $M$ is placed in a non-uniform magnetic field $B$. If the gradient of the field is $\frac{dB}{dx}$ along the axis of the magnet, the force on the magnet is:

Two identical short bar magnets, each of magnetic moment $M$, are placed perpendicular to each other at a distance $d$ apart. The magnetic field at a point midway between them on the line joining their centers is:

A bar magnet is cut into two equal pieces along its length. The magnetic moment of each piece becomes:

A bar magnet of magnetic moment $M$ is bent into a semicircle. The new magnetic moment is:

A magnetic dipole of moment $M$ is aligned at an angle $heta$ with a uniform magnetic field $B$. The work done in rotating it by an angle $dheta$ is:

A short bar magnet placed with its axis at 30° with an external field of 800 G experiences a torque of 0.016 Nm. The magnetic moment of the magnet is:

A thin wire of length 'L' is bent into a planar loop of irregular shape. A current 'I' flows through it. The loop is placed in a uniform magnetic field 'B' with its plane perpendicular to the field. If the magnetic moment of a circular loop of same perimeter and carrying same current is $\mu_c$, the magnetic moment ($\mu$) of the irregular loop satisfies:

Two identical magnetic dipoles of magnetic moment 'm' are placed at a distance 'd' apart with their axes perpendicular to each other. The resultant magnetic moment of the combination is:

A magnetic dipole of moment $m = 0.1 Am^2$ is placed in a uniform magnetic field $B = 0.2 T$ with its axis making an angle of 60° with the field. The magnitude of the torque acting on the dipole is:

Two short bar magnets of magnetic moments 'M' each are arranged at the opposite corners of a square of side 'd' such that their centres coincide with the corners and their axes are parallel. If the like poles are in the same direction, the magnetic induction at any of the other corners of the square is: