Question 5 (20 marks)
(a) Write down the equation that represent the force,
F_(c), exerted
(2 marks)
on a charge,
q, that is located in the point of space where an
electric field,
E, exists.
(b) Write down the equation that represent the magnetic force,
(2 marks)
F_(m), acting on a charge,
q, that is moving in a velocity,
v,
through a magnetic field,
B, where
\theta is the angle between
v
and
B.
(c) A 500-turn coil is placed in a magnetic field that varies
(4 marks)
uniformly from 100 mWbb to 20 mWbb in 5 seconds. Calculate
the induced emf in the coil.
(d) A four-pole synchronous AC generator with a smooth air gap
(4 marks)
has a distributed rotor winding with 260 series turns, a winding
factor of 0.935 , and an air gap of length 0.7 mm . Assuming the
mmf drop in the electrical steel to be negligible, find the rotor-
winding current required to produce a peak, space-
fundamental magnetic flux density of 1.8 T in the machine air
gap.
(e) List down the differences between concentrated winding and
(8 marks)
distributed winding.
