Bits
MULTIPLE CHOICE QUESTIONS
1. S.I. units of magnetic flux density are
A) Weber B) Weber/m2 C) Tesla D) Weber/m2, Tesla
2. Units for magnetic flux in S.I. system are
A) Weber/m2 B) Weber/cm2 C) Tesla D) Weber
3. The force applied by a remote controller on a TV is
A) Magnetic B) Electrical C) Field D) None of these
4. Solenoid is a ..... shaped Coil.
A) Circular B) Elliptical C) Spiral D) None of these
5. Solenoid works as ...... when current passes through it.
A) bar magnet B) horse shoe C) transformer D) None of these
6. The direction of lines of force in the outerside of a solenoid is
A) North to South B) South to North C) East to West D) West to East
7. The direction of lines of force in the innerside of a solenoid is
A) North to South B) South to North C) East to West D) West to East
8. The magnetic lines of force are
A) Closed B) Open C) Circles D) Eclipses
9. In a uniform magnetic field ..... is constant.
A) Magnetic field induction B) Magnetic flux C) Field direction D) All the above
10. Direction of induced current in a conductor is determined by ...... rule.
A) Fleming's left hand rule B) Fleming's right hand rule
C) Ampere's left hand rule D) Ampere's right hand rule
11. Which of the following instruments works by electromagnetic induction?
A) Motor B) Telephone reciever C) Dynamo D) All the above
12. Formula for magnetic flux density
A) B = 
I B) B = 
C) B = 
D) B = 
13. CGS units for magnetic flux density are
A) Weber B) Gause C) Tesla D) None
14. e.m.f. can be induced in a loop by
A) Changing the field induction B) Changing the area of a loop
C) relative motion of magnet coil D) All the above
15. ..... Works on the rule of magnetic induction.
A) Induction stove B) Tape recorder C) ATM card D) All the above
16. Which of following converts mechanical energy into electrical energy?
A) Motor B) AC dynamo C) DC generator D) AC dynamo and DC generator
17. A motor converts ...... energy to ..... energy.
A) Mechanical, Electrical B) Electrical, Mechanical
C) Electrical to light D) All the above
18. In an AC generator the direction of current changes because of
A) Sliprings B) Carbon brushes C) External Magnet D) All the above
19. Speed of a motor depends on
A) Number of turnings B) Electrical current C) Area of armature D) All the above
20. Which of the following can produce an electric current in a circuit?
A) A motor B) A generator C) Capacitor D) None
21. The number of lines passing through the plane of area 'A' perpendicular to the field is called .....
A) Magnetic field B) Electrical induction C) Magnetic flux D) Magnetic force
22. Tesla = .....
A) 10-4 gauss B) 106 gauss C) 104 gauss D) 10-6 gauss
23. Match the following.
|
1) Electric Generator (AC) |
a) Electric Magnetic Induction |
|
2) Solenoid |
b) Two slip rings |
|
3) Electric Motor |
c) Two commutators |
|
4) Electric Generator (DC) |
d) Soft iron rod |
A) 1-b, 2-d, 3-c, 4-a B) 1-a, 2-d, 3-b, 4-c C) 1-b, 2-a, 3-c, 4-d D) 1-b, 2-d, 3-a, 4-c
24. In an electric motor, conversion takes place of ....
A) Electrical energy into light B) Chemical energy into electrical energy
C) Electrical energy into chemical energy D) Electrical energy into mechanical energy.
25. Which of the following has its working based on electromagnetic induction.
A) Voltmeter B) Ammeter C) Galvanometer D) Transformer
26. The magnetic field lines inside a current carrying solenoid are
A) circular, but they do not intersect each other.
B) Circular at the ends inside the solenoid.
C) Among the axis and parallel to each other.
D) Circular, but they do not intersect each other.
27. A soft iron bar is introduced inside a current carrying solenoid. The magnetic field inside the solenoid
A) will be Zero B) will remain same C) will decreases D) will increases
28. If the number of turns per unit length of a coil of a solenoid is doubled, the self inductance of the solenoid will
A) Be halved B) Become four times C) Remain D) Be doubled
29. The magnetic field inside a long straight solenoid - carrying current
A) Is the same at all points B) Increases as we move towards its end
C) Decreases as we move towards its end D) is Zero
30. The essential difference between an AC generator and a DC generator is that ....
A) AC generator will generate a higher voltage
B) DC generator will generate a higher voltage
C) AC generator has an electromagnet while a DC generator has permanent
D) AC generator has slip rings while the DC generator has a commutator
31. Commercial Electric motors do not use ....
A) A soft iron core on which the coil is wound
B) An electro magnet to rotate the armature
C) Effectively large number of turns of conducting wire in the current carrying coil.
D) A permanent magnet to rotate the armature.
32. Which of the following converts electrical energy into mechanical energy?
A) Generator B) Motor C) Battery D) Solenoid
33. Which of the following converts Mechanical energy to electrical energy?
A) Generator B) Motor C) Battery D) Solenoid
34. A horse shoe magnets' two poles are kept on both sides to a current carrying conductor. In this experiment the direction of force is observed as
A) current wire deflects towards the North pole of Magnet
B) current wire deflects towards the south pole of Magnet
C) No deflection in the wire
D) the wire deflects according to right hand thumb rule
35. "Induced current is in such a direction which appeals the change in flux". This law is known as
A) Faraday's law B) Fleming's law C) Lenz's law D) Tesla's law
36. Magnetic field lines are
A) Geometric lines B) Real lines C) Imaginary lines D) Induction lines
37. Scientist who discovered the laws of electromagnetic induction?
A) Maxwell B) Plank C) Faraday D) Weber
38. The Mathematical form of Faraday's law of electromagnetic induction is 
Answers: 1-D; 2-D; 3-C; 4-C; 5-A; 6-A; 7-B; 8-A; 9-D; 10-B; 11-C; 12-C; 13-B; 14-D; 15-D; 16-D; 17-B; 18-A; 19-D; 20-B. 21-C; 22-C; 23-D 24-D; 25-D; 26-C; 27-D 28-B; 29-A; 30-D; 31-D 32-B; 33-A; 34-D; 35-C 36-C; 37-C; 38-A.
