Question

In a circular coil of radius r, the magnetic field at the centre is proportional to
(a) r²
(b) r
(c) 1/2

Answer 1

In a circular coil of radius r, the magnetic field at the center is proportional to 1/r or reciprocal of radius.

       (The question is incomplete and it should have an option (d) stating 1/r).

• The magnetic field of a circular coil is influenced by the current flowing through it, the number of turns it has, and its radius.

• Magnetic field (B) = 1 / r

• Magnetic field (B) = μ₀NI / 2r (where r is the radius of the circular coil)
• The magnetic field of the coil is inversely proportional to its radius.
• As a result, as the radius rises, the magnetic field at the center of the circular coil drops, while the magnetic field at the center of the coil increases.