Question

(a) Define the term ‘self-inductance’ of a coil. Write its S.I. unit.
(b) A rectangular loop of sides a and b carrying current is kept at a distance ‘a’ from an infinitely long straight wire carrying current as shown in the figure.

Obtain an expression for the resultant force acting on the loop.

Answer 1

Answer:

(a) The self inductance is defined on the magnetic flux linked with the coil when unit current flows through it. The self inductance is defined as the emf induced in the coil, when the rate of change of current in the coil is 1 ampere/second. The SI unit of self inductance is henry (H).

b)We know the magnetic field due to an infinitely long current-carrying wire is given by

where H/m

i = current carried by infinite wire

r = perpendicular distance of wire to the point

Force on a straight wire is given by,  

Using right-hand rule, we can find the direction of the magnetic field for I1.

According to Fleming's right-hand rule, the thumb, forefinger and middle finger of the right hand are stretched perpendicular to each other as shown in the illustration shown below, and if the thumb represents the direction of the movement of conductor, fore-finger represents direction of the magnetic field, then the middle finger represents direction of the induced current.