Question

A ring having a cross-sectional area of 500 mm^2, a circumference of 400 mm and ϕ=800microWb has a coil of 200 turns wound around it. Calculate the flux density of the ring.

(a) 1.6T

(b) 2.6T

(c) 3.6T

(d) 4.6T

The question was asked in a national level competition.

Origin of the question is Ohm’s Law for a Magnetic Circuit topic in chapter Simple Magnetic Circuits of Basic Electrical Engineering

Answer 1

Right answer is (a) 1.6T

Explanation: ϕ=BA => Flux density B = ϕ/A

Substituting the values, we get B=1.6T.