Question

An iron ring of mean circumference of 140cm and cross sectional area of 12cm2 is wound with 500 turns of wire. What is the relative permeability of iron if exciting current of 2A flowing in a coil produces flux of 1.2mWb ​

Answer 1

Answer:

2.5J

Explanation:

B = μ0 μr NI/l Wb/m2

∴ 1 = 4π × 10− 7 × 1000 × 400 I/0.2π or I = 1.25 A Now L = μ0 μr AN2/l = 4π × 10− 7 × 103 × 100 × 10− 4 × 4002 /0.2π = 32.HE = 1/2LI2 = 1/2 x 3.2 x 1.252 = 2.5J