The expected answers were:
(a) In an electric circuit, insulation confines current to a definite path but in
the magnetic circuit there is no known insulation and therefore not all flux
is confined to one path.
OR
In the electric circuit, resistance is almost constant apart from changes due to
temperature but in the magnetic circuit reluctance varies over a wide range
due to changes in permeability.
(b)(i) 8 x 2.5 = 20V
(ii)3 - 2.5 = O.5A
(iii )Resistor X 20 /0.5
=40Ω
The question was on Direct Current Circuit Theory. The question was
surprisingly unpopular. The performance was poor.
Many candidates could not state the difference between electric and
magnetic circuits. Many of them that attempted the part (b) could not
also show a good understanding of KCl, characteristics of a parallel
circuit and Ohm's law.