Question

A circular coil a carrying current produces a magnetic field $B_0$ at its centre. This coil is made itself to $10$ turns and the same current is set up in it. The magnetic field $B$ at its centre would be

• A. $B=B_0$
• B. $B=10B_0$
• C. $B=50B_0$
• D. $B=100B_0$

Answer 1

The correct option is B $B=10B_0$

Electric current in a circular loop creates a magnetic field which is more concentrated in the center of the loop than outside the loop. Concentric circles are formed, which are centered at the point on both sides of the loop. The lines near the center of the loop are almost straight. The magnetic field at the center of the loop is perpendicular to the plane of the loop. The concentric circles become larger as we move away from the wire because as the distance increases from the current carrying conductor the strength of the magnetic field fades away.
In same way, when we consider an electric current passing through a circular coil with n number of turns, say a solenoid, the strength of the magnetic field is directly proportional to the number of turns of the solenoid. That is, as the number of turns increases in the coil, the strength of the solenoid also increases. Therefore, the number of turns increases by 10, then the magnetic field strength also increases by 10 times.
That is, ${B=10B}_0$.