Top 250+ Solved Electromagnetic Theory MCQ Questions Answer
Q. Main causes of noisy solenoid are
a. strong tendency of fan out of lami-nations at the end caused by repul¬sion among magnetic lines of force
b. uneven bearing surface, caused by dirt or uneven wear between moving and stationary parts
c. both of above
d. none of the above
Q. Core of an electromagnet should have
a. low coercivity
b. high susceptibility
c. both of the above
d. none of the above
Q. Magnetism of a magnet can be destroyed by
a. heating
b. hammering
c. by inductive action of another magnet
d. by all above methods
Q. An air gap is usually inserted in magnetic circuits to
a. increase m.m.f.
b. increase the flux
c. prevent saturation
d. none of the above
Q. The relative permeability of a ferromagnetic material is
a. less than one
b. more than one
c. more than 10
d. more than 100 or 1000
Q. Permeability in a magnetic circuit corresponds to______ in an electric circuit.
a. resistance
b. resistivity
c. conductivity
d. conductance