Magnetic field lines due to current - class-XI

The magnetic field are concentric circle at point of a current carrying circular conductor direction of the magnetic field of every section of the circular loop can be found by using the right hand thumb rule .if you curl your right hand fingers in direction of magnetic field your thumb will point in the direction of the current flow.

Using Right Hand thumb rule, as current direction reverses, you need to reverse the hand and direction of magnetic field reverses.

Using Ampere's Law for an infinite cylinder, the magnetic field at a point inside is determined by the current enclosed. The vector direction is perpendicular to the radial vector from the axis.

For a circular loop of radius R carrying current, I placed in $x-y$ plane, the magnetic moment $M= I,,\pi R^2$. It acts perpendicular to the loop i.e., along with the z-direction. When half of the current loop is bent in y-z plane, the magnetic moment due to half current loop in x-y plane,$ M _1 = I \left (\dfrac {\pi R^2}{2} \right )$ acting along z-direction.
Magnetic moment due to half current loop in y-z plane,$ M _2 = I \left (\dfrac {\pi R^2}{2} \right )$ along x-direction.
Effective magnetic moment due to entire bent current loop,
$M'$ =$\sqrt{{M _{1}^{2}}+ {M _{2}^{2}}} $=$\sqrt {{\left (\dfrac{I \pi R^2}{2} \right )^2}+{\left (\dfrac{I \pi R^2}{2} \right )^2}}$
$M'=\dfrac{I\pi R^2}{2}\sqrt2 <M$
i.e., magnetic moment diminishes.

A Toroid is a solenoid which is bent in the form of a ring with its both the ends joined together.  Since both the ends are merged, it appears endless.

A solenoid is a long coil of wire wrapped in a cylindrical shape, which creates a uniform magnetic field inside when current flows through it.

Electric current and magnetism are very closely related phenomenon and both can be generated using the other.

Electromagnetism is study of various phenomenon related to electricity and magnetism. 

Electric current and magnetism are very closely related phenomenon and both can be generated using the other.

Direction of magnetic field lines around a current carrying conductor can be found by RIght Hand Thumb Rule.

According to the right-hand rule, the magnetic field lines around a straight current-carrying conductor form concentric circles centered on the wire.