Magnetic Field Due to a Current Carrying Conductor

Chapter-4|Moving Charges and Magnetism| NCERT 12th Physics:

Magnetic Field Due to a Current Carrying Conductor:

Magnetic Field On The Axis of a Circular Current Carrying Loop:

Let we consider a circular loop of radius R with Centre C.

Let we consider current element Idl on the top and the bottom.

Now, magnetic field at point P due to current element Idl, According to Biot-Savart’s law

Now, Resolving dB due to current element Idl at top and bottom balance each other. The net magnetic field is obtained only by the Sine component.

Note:  When the direction of current in the coil is anti-clockwise, then direction of magnetic field is away from the loop.