Question

Magnetic field intensity at the centre of a circular coil theory

Answer 1

The intensity of magnetic field at the centre O due to the entire coil, ∑AB=∑4πr2μoiΔl [∵sin90o=1] B=4πr2μoi∑Δl=4πμor2i×2πrn.

Answer 2

The magnetic field lines due to a circular coil is shown in the given figure .At every point of a current carrying circular loop, the concentric circles represent the magnetic field around it . At the centre of loop, the field appears to be a straight line.The magnetic field produced by current carrying circular wire at a given point on the following factors.

1. Amount of current flowing through a wire

-The strength of magnetic field (B) due to a current carrying circular wire is directly proportional to the amount of current (I) flowing through it. i.e.

$B \infty I$

2. Number of turns of the circular wire -

The strength of the magnetic field due to a current carrying circular wire is directly proportional to the number of turns (N) of the wire

. i.e. -

$B \infty \: N$

Thus the strength of magnetic field produced by a current carrying circular coil can be increased by

(a) Increasing the number of turns of wire in the coil.

(b) Increasing the current flowing through the coil.

(c) Decreasing the radius of the coil.