The expected answers were:
(a)(i) Magnetic flux density is the amount of magnetic flux per unit area of a
section, perpendicular to the direction of flux.
B = Φ
A
where B = magnetic flux density in Tesla (T)
Φ = magnetic flux in webers (Wb)
A = area in square metres (m2)
The S. I. unit of magnetic flux density in weber per square metre (Wb/m2)
(ii) Magnetic flux is the group of magnetic field lines emitted outward from
the north pole of a magnet. The symbol for magnetic flux is Φ (phi).
The S. I. unit of magnetic flux is the weber (Wb)
(b) E = 1.375v
L = 0.25cm = 2.5 x 10-3m
v = 5ms-1
E = Blv
: . B = E
Lv
B = 1.375
2.5 x 10-3 x 5
B = 110 Wb/m2
This question was on magnetic field. Many candidates could not just give the definitions of B and Φ correctly.
Many candidates did not convert from centimetres to metres thus getting the final answer wrong.