Top 80+ Solved Magnetism and Electromagnetism MCQ Questions Answer
Q. A certain amount of current flows through a ring-shaped coil with fixed number of turns. How does the magnetic induction B varies inside the coil if an iron core is threaded into coil without dimensional change of coil ?
a. Decreases
b. Increases
c. Remains same
d. First increases and then decreases depending on the depth of iron in¬sertion
Q. The magnetic reluctance of a material
a. decreases with increasing cross sectional area of material
b. increases with increasing cross-sec-tional area of material
c. does not vary with increasing cross-sectional area of material
d. any of the above
Q. The initial permeability of an iron rod is
a. the highest permeability of the iron rod
b. the lowest permeability of the iron rod
c. the permeability at the end of the iron rod
d. the permeability almost in non-magnetised state
Q. How does the magnetic compass needle behave in a magnetic field ?
a. It assures a position right angle to magnetic field
b. It starts rotating
c. It assures a position which follows a line of magnetic flux
d. None of the above
Q. In a simple magnetic field the strength of magnet flux
a. is constant and has same value in energy part of the magnetic field
b. increases continuously from initial value to final value
c. decreases continuously from initial value to final value
d. first increases and then decreases till it becomes zero
Q. For which of the following materials the saturation value is the highest ?
a. Ferromagnetic materials
b. Paramagnetic materials
c. Diamagnetic materials
d. Ferrites
Q. The magnetic materials exhibit the property of magnetisation because of
a. orbital motion of electrons
b. spin of electrons
c. spin of nucleus
d. either of these
Q. For which of the following materials the net magnetic moment should be zero ?
a. Diamagnetic materials
b. Ferrimagnetic materials
c. Antiferromagnetic materials
d. Antiferrimagnetic materials
Q. The attraction capacity of electromagnet will increase if the
a. core length increases i
b. core area increases
c. flux density decreases
d. flux density increases
Q. Which of the following statements is correct ?
a. The conductivity of ferrites is better than ferromagnetic materials
b. The conductivity of ferromagnetic materials is better than ferrites
c. The conductivity of ferrites is very high
d. The conductivity of ferrites is same as that of ferromagnetic materials
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