Question

a toroid of 4000 turn has outer radius 26 cm and inner radius 25 cm if the current in the wire is 10 A calculate the magnetic field of the wire​

Answer 1

Explanation:

(a)magnetic field outside is zero. It is non zero only inside the core of a toroid.

By definition, Ampere's Law states that integration of magnetic field over an amperian loop is equivalent to constant μ multiplied by current enclosed. Now, the current that flows at outer circumference and inner circumference of toroid are in opposite direction to each other. Therefore, current enclosed by Amperian loop is zero. Thus, magnetic field outside the toroid is zero.