Case: Read the passage and answer the below questions
The toroid is a hollow circular ring on which a large number of turns of wire are closely wound. It can be viewed as a solenoid that has been bent into a circular shape to close on itself. The magnetic field vanishes in the open space inside and outside the toroid. The magnetic field inside the toroid is constant in magnitude and is given by B = µ0 n I, where n is the number of turns per unit length and I is the current flowing in the toroid, and µ0 is the absolute permeability of the free space.
Magnetic field due to a current carrying toroid is independent of;
Answer & explanation
Correct answer: option 4
Magnetic' field due to a solenoid having n number of turns per metre and carrying current I is B= µ0 n I , n = N/2πr which, is independent of the length and area of cross-section of the solenoid.