Magnetism and Electromagnetism Multiple choice Questions and Answers-1 (English)

1. Tesla is a unit of
(A) field strength
(B) inductance
(C) flux density
(D) flux
Ans: C

2. A permeable substance is one
(A) which is a good conductor
(B) which is a bad conductor
(C) which is a strong magnet
(D) through which the magnetic lines of force can pass very easily
Ans: D

3. The materials having low retentivity are suitable for making
(A) weak magnets
(B) temporary magnets
(C) permanent magnets
(D) none of the above
Ans: B

4. A magnetic field exists around
(A) iron
(B) copper
(C) aluminium
(D) moving charges
Ans: D

5. The ratio of intensity of magnetisation to the magnetisation force is known as
(A) flux density
(B) susceptibility
(C) relative permeability
(D) none of the above
Ans: B

6. Magnetising steel is normals difficult because
(A) it corrodes easily
(B) it has high permeability
(C) it has high specific gravity
(D) it has low permeability
Ans: D

7. The main constituent of permalloy is
(A) cobalt
(B) chromium
(C) nickel
(D) tungsten
Ans: C

8. The use of permanent magnets is. not made in
(A) magnetoes
(B) energy meters
(C) transformers
(D) loud-speakers
Ans: C

9. Paramagnetic materials have relative permeability
(A) slightly less than unity
(B) equal to unity
(C) slightly more than unity
(D) equal to that ferromagnetic mate rials
Ans: C

10. The left hand rule correlates to
(A) current, induced e.m.f. and direction of force on a conductor
(B) magnetic field, electric field and direction of force on a conductor
(C) self induction, mutual induction and direction of force on a conductor
(D) current, magnetic field and direction of force on a conductor
Ans: D

11. The unit of relative permeability is
(A) henry/metre
(B) henry
(C) henry/sq. m
(D) it is dimensionless
Ans: D

12. Ferrites are materials.
(A) paramagnetic
(B) diamagnetic
(C) ferromagnetic
(D) none of the above
Ans: C

13. Air gap has_______eluctance as compared to iron or steel path
(A) little
(B) lower
(C) higher
(D) zero
Ans: B

14. The direction of magnetic lines of force is
(A) from south pole to north pole
(B) from north pole to south pole
(C) from one end of the magnet to another
(D) none of the above
Ans: B

15. Which of the following is a vector quantity ?
(A) Relative permeability
(B) Magnetic field intensity
(C) Flux density
(D) Magnetic potential
Ans: B

16. In the left hand rule, forefinger always represents
(A) voltage
(B) current
(C) magnetic field
(D) direction of force on the conductor
Ans: C

17. Which of the following is a ferromagnetic material ?
(A) Tungsten
(B) Aluminium
(C) Copper
(D) Nickel
Ans: D

18. Ferrites are a sub-group of
(A) non-magnetic materials
(B) ferro-magnetic materials
(C) paramagnetic materials
(D) ferri-magnetic materials
Ans: D

19. Gilbert is a unit of
(A) electromotive force
(6) magnetomotive force
(C) conductance
(D) permittivity
Ans: B

20. Which of the following is the unit of magnetic flux density ?
(A) weber
(B) lumens
(C) tesla
(D) none of the above
Ans: C