Current is flowing in a coil of area A  and number of turns N, then magnetic moment of the coil, M is equal to :

A uniform magnetic field acts right angles to the direction of motion of electrons.  As a result, the electron moves in a circular path of radius 2 cm.  If the speed of electrons is doubled, then the radius of the circular path will be :

A current carrying coil is subjected to a uniform magnetic field. The coil will orient so that its plane becomes 

A straight wire of length 0.5 m and carrying a current of 1.2 A is placed in uniform magnetic field of induction 2 T.  The magnetic field is perpendicular to the length of the wire. The  force on the wire is :

Magnetic field due to 0.1 A current flowing through a circular coil of radius 0.1m and 1000 turns at the centre  of the coil is :

Tesla is the unit of :

The magnetic field at a distance  r from a long wire carrying current  I is 0.4 T.  The magnetic field at a distance 2r is :

A coil of one turn is made of a wire of certain length and then from the same length a coil of two turns is made. If the same current is passed is both the cases, then the ratio of the magnetic induction at their centers will be :

A galvanometer of resistance 50 Ω is connected to a battery of 3 V along with a resistance of 2950 Ω in series. A full scale deflection of 30 divisions is obtained in the galvanometer. In order to reduce this deflection to 20 divisions, the resistance in series should be :

The magnetic induction at a point P which is at the distance of 4 cm from a long current carrying  wire is 10^-3 T.  The field of induction at a distance 12 cm from the current will be :