Moving Charges And Magnetism

The magnetic effect of current was first discovered by H.C. Oersted. He observed that the flow of charges in a conductor produces magnetic effect around it. 

Right-Hand Thumb Rule
According to this rule, if we grasp the current-carrying wire in our right hand such that our thumb points in the direction of current, then the direction in which our fingers encircle the wire will tell the direction of the magnetic field lines around the wire.

The Biot–Savart Law

• 

• ​According to this law, the magnetic field is proportional to the current and element length and inversely proportional to the square of the distance.

• $dB= \frac{Idl\sin \theta }{r^2}$

Magnetic field due to a current-carrying circular coil

• At the centre, it is calculated to be equal to B.

  • $B=\frac{{\mu }_{0}nI}{r}$

  • Here,
    n = Number of turns in the coil
    I = …