SULIT
Question 2
CO2, PO2, WP1, C3
a) A coil of 300 turns is wound uniformly on a ring of non-magnetic material. The ring
has a mean circumference of 40 cm and a uniform cross-sectional area of 4cm². If the
current in the coil is 5 A, calculate;
i. the magnetic field strength.
(3 Marks)
ii. the flux density and.
(3 Marks)
iii. the total magnetic flux in the ring.
(3 Marks)
b) For the series magnetic circuit in Figure 2,
a. Find the number of turns $N_1$ required to establish a flux $\phi = 12 \times 10^{-4}$ Wb in the
magnetic circuit in Figure 2.
(3 Marks)
b. Find the permeability $\mu$ of the material.
(3 Marks)
1 =
2 A
N1
?
Cast steel
Area = 0.0012 m²
I = 1 A
N? = 30 turns
$l_m$ (mean length) = 0.2 m
Figure 2: Magnetic Circuit
