Embibe Experts Solutions for Chapter: Magnetic Effect of Current, Exercise 1: Exercise-1

The electric charge in uniform motion produces-

Two parallel wires carrying electric current in the same direction will attract each other because.

Four wires of equal length are bent in the form of four loops $P, Q, R$ and $S.$ These are suspended in a uniform magnetic field and same current is passed in them. The maximum torque will act on.

A bar magnet has a magnetic moment $2.5 \mathrm{J} {\mathrm{T}}^{-1}$ and is placed in a magnetic field of $0.2 \mathrm{T}.$ Work done in turning the magnet from parallel to antiparallel position relative to the field direction.

Assertion : A direct uniformly distributed current flows through a solid long metallic cylinder along its length. It produces magnetic field only outside the cylinder.

Reason : A thin long cylindrical tube carrying uniformly distributed current along its length produces a magnetic field inside it. Moreover, a solid cylinder can be supposed to be made up of many thin cylindrical tubes.

Assertion : Two charged particles are released from rest in gravity free space. After some time, one particle will exert a non-zero electrostatic force on the other particle.

Reason : A moving charge cannot produce magnetic field. But a magnetic force may act on a charged particle moving in an external magnetic field.

Assertion : A current carrying wire is placed in magnetic field which is not parallel to its length, than magnetic force acts on it

Reason : Free electrons and positive ions are in motion inside any current carrying wire

Assertion : The density of field lines decreases in a medium of high permeability

Reason : Because $B\propto \frac{1}{\mu }$