The expected answers were:
Number of turns, n = 300
Mean length, 1= 900mm = 0.9m
Cross-sectional area, A = 400mm7² = 400 x 10–6m²
Current through coil, I = 6A
(a)The magnetic field strength
H = NI/I
= 300 x 6/α
= 2000A/m
(b)The flux density, B = µoµoH
= 4Π X 10-7x 1x 2000
= 2.513mT/0.00251T/2.513 x 10–3T
(c)Total flux, φ = BA
= 2.513 X 10–3X 400 X 0–6 = 1.005µb
The question was on Electromagnetic fields. The question was unpopular
with the candidates. Very few candidates attempted this question with
fair performance.
