 |
| Physics 10th Chapter 15 Electromagnetism Questions Bank |
Physics 10th Chapter 15 Electromagnetism Solved MCQs, Short and Long Questions
MCQs
Select the right Answer.
1. ____________ is a study of magnetic effects of current:
2. A closely wound cylindrical coil of insulated wire is
3. A coil in which current is induced is known as
4. A device used to convert mechanical energy into electrical energy
5. A device which is used to convert electrical energy into rotational kinetic energy
6. A generator is a ____ with its inputs and outputs reversed
7. A generator works on the principle of
8. A practical application of mutual induction is
9. A transformer has 100 turns in primary and 500 turns in the secondary. If 6 Volts D.C is applied across its primary, the voltage induced across its secondary would be
10. According to Faraday’s law of induced emf is ____proportional to change in flux
11. An electrical device which is used to increase or decrease the value of alternating voltage
12. Direction of magnetic lines of force in straight conductor is found by
13. Electric power is usually generated at places which are far from the places where it is
14. Electromagnet is used in device
15. Electromagnetic induction was discovered by
16. Force on current carrying conductor in a magnetic field is found by
17. Hold down the end of the current carrying solenoid in front of you, if the direction of current flow through this end is anti-clock wise it would be
18. Hold down the end of the current carrying solenoid in front of you, if the direction of current flow through this end is clockwise it would be
19. If the current is flowing from bottom to top then the direction of magnetic lines of force will be
20. If the current is flowing from top to bottom then the direction of magnetic lines of force will be
21. If the Current is induced in a circuit due to change of current in an other circuit, this process is known as
22. If the current through a coil or a circuit changes and this change induces an emf in the circuit itself, this process is known as
23. In D.C motor coil can rotate in magnetic field by an angle of
24. In step-up transformer
25. Law of electromagnetic induction and electrolysis were presented by
26. Lines of force in solenoid resemble the pattern of lines of force due to
27. Magnetic field in most part of the coil is
28. Magnetic field of coil Is identical to field of ________ magnet.
29. Magnetic lines of force in solenoid are
30. Micheal Faraday belonged to _______
31. MRI stands for
32. Number of turns on secondary coil is
33. Number of turns on the primary coil is represented as
34. Shape of magnetic lines of force in straight conductor are
35. Step down transformer
36. The Coil of transformer in which alternating voltage is induced is known as
37. The coil of transformer in which change in current produces induced current in another coil is known as
38. The coil which is connected to the alternating voltage whose value is to be altered is known as
39. The magnetic field produced in straight current carrying conductor is stronger:
40. The magnetic field produced in straight current carrying conductor is weaker
41. The magnetic lines of force can be traced on cardboard by using
42. The magnitude of induced emf depends upon the speed of
43. The number of magnetic lines of force passing through any surface
44. The polarity of current carrying solenoid is found by
45. The value of induced emf is directly proportional to the rate of change of
46. Transformer is called step-down when
47. Transformer is used to
48. Transformer is used to change the value of
49. Transformer works on the principle of
50. Transformers are used to
51. Type of transformer which is used to decrease the value of alternating voltage
52. Type of transformer which is used to increase the value of alternating voltage
53. Types of transformer are
54. Voltage of current supplied to consumers is
55. Walk through metal detector are installed at airport and other places for
56. Weak ionic current that travel along the nerve can produce the
57. When a straight current carrying conductor is placed in a magnetic field at right angle to it, the direction of force acting on conductor is
58. When current passes through straight conductor it produce magnetic field in the form of:
59. Which device is based on the principle of electromagnetism?
60. Which is an electric switch that opens and closes under the control of another electrical circuit?
61. Which part of DC motor reverses the direction of current through coil every half cycle?
62. Which thing work on the phenomenon of electromagnetic induction in hydroelectric power plant?
63. Who discovered left hand rule?
64. Who discovered that when current passes through a conductor it produces a magnetic field around it
65. Who discovered the phenomenon of electromagnetic induction?
66. Who found the direction of induced e.m.f first time?
Short Questions
1. A conductor wire generates a voltage while moving through a magnetic field. In what direction should the wire be moved, relative to the field to generate the maximum voltage?
2. A wire lying perpendicular to an external magnetic field carries of a current in the direction shown in the diagram below. In what direction will the wire move due to the resulting magnetic force?
3. Can a transformer operate on direct current?
4. Can a transformer work on D.C?
5. Define A.C. Generator.
6. Define electromagnetic induction.
7. Define ideal transformer.
8. Define mutual induction.
9. Define self-Induction.
10. Define step down transformer and step up transformer.
11. Define transformer.
12. Explain working principle of relay circuit.
13. How electricity is produce by electromagnetic induction?
14. How magnetic lines of force are formed in the straight current carrying conductor?
15. How voltages are stepped down?
16. Illustrate diagrammatically the similarity between magnetic field of a bar magnet and that of a coil.
17. Is it possible that a constant current flowing in a coil produces an induced current in another coil?
18. Prove that Lenz law is a manifestation of the law of conservation of energy.
19. State and explain the rule by which the direction of the lines of force of the magnetic field around a current-carrying conductor can be determined.
20. State Faraday law of Electromagnetic Induction.
21. State Fleming’s Left Hand Rule.
22. State Lenz’s law?
23. Suppose someone handed you three similar iron bars and told you one was not magnet, but the other two were. How would you find the iron bar that was not magnet?
24. Suppose we hang a loop of wire so that it can swing easily. If we now put a magnet into the coil, the coil will start swinging. Which way will it swing relative to the magnet, and why?
25. Suppose you have a coil of wire and a bar magnet. Describe how you could use them to generate an electric current.
26. What is the difference between a generator and a motor?
27. What reverses the direction of electric current in the armature coil of D.C motor?
28. What are the factors which increase force on a current carrying conductor?
29. What are uses of transformer?
30. What do you know about primary coil and secondary coil?
31. What do you understand by the term mutual induction?
32. What factors affect induced emf?
33. What is difference between magnetism and electricity?
34. What is meant by strength of magnetic field? When it is maximum and minimum?
35. What is relay circuit?
36. What is Right Hand Grip Rule?
37. What is Solenoid?
38. What is the function of core in the transformer?
39. What is working principle of transformer?
40. When a straight current-carrying conductor is placed in a magnetic field, it experiences a force. State the rule by which the direction of this force can be found out.
41. When the force on the current carrying conductor in a magnetic field is maximum and when it is minimum?
42. Which device is used for converting electrical energy into mechanical energy?
43. Which device convert mechanical energy into electrical energy in hydroelectric dam?
44. Why alternating voltage is stepped up at the generating station?
45. Why is the voltage used for the domestic supply much lower than the voltage at which the power is transmitted?
46. Why mains power is supplied as alternating current?
47. Write down the principle of A.C. generator
48. Write down the rules to find the polarity of solenoid.
49. You are given an unmarked magnetized steel bar and bar magnet, its north and south ends are marked N and S respectively. State how would you determine the polarity at each end of the unmarked bar?
Long Questions
1. Demonstrate by an experiment that a magnetic field is produced around a straight current-carrying conductor .
2. State and explain the rule by which the direction of the lines of force of the magnetic field around a current-carrying conductor can be determined.
3. State that a current-carrying coil in a magnetic field experiences a torque.
4. What is an electric motor? Explain the working principle of D.C motor .
5. Describe a simple experiment to demonstrate that a changing magnetic field can induce e.m.f. in a circuit.
6. What are the factors which affect the magnitude of the e.m.f. induced in a circuit by a changing magnetic field?
7. Describe the direction of an induced e.m.f. in a circuit? How does this phenomenon relate to conservation of energy?
8. Draw a labelled diagram to illustrate the structure and working of A.C generator .
9. What is a transformer? Explain the working of a transformer in connection with mutual induction.
10. The voltage chosen for the transmission of electrical power over large distances is many times greater than the voltage of the domestic supply. State two reasons why electrical power is transmitted at high voltage.
11. When a straight current carrying conductor is placed in a magnetic field, it experiences a force. State the rule by which the direction the direction of this force can be found out?
12. What is electromagnetic induction? Describe simple experiments to demonstrate that a changing magnetic field can induce an e.m.f in a circuit?
13. State Faraday's law. How the direction of induced e.m.f is determined by Len's law?
14. Write the working of AC generator. How current is produced from a generator?
15. What do you understand by the term mutual induction? Name and define SI unit of mutual inductance?
16. Briefly write about the high voltage transmission.
17. Write applications of electromagnet.
18. A transformer is needed to convert a mains 240 V supply into a 12 V supply. If there are 2000 turns on the primary coil, then find the number of turns on the secondary coil.
19. A step-up transformer has a turn ratios of 1 : 100. An alternating supply of 20 V is connected across the primary coil. What is the secondary voltage?
20. A step-down transformer has a turns ratio of 100 : 1. An ac voltage of amplitude 170 V is applied to the primary. If the current in the primary is 1.0 mA, what is the current in the secondary?
21. A transformer, designed to convert the voltage from 240 V a.c mains to 12 V, has 4000 turns on the primary coil. How many turns should be on the secondary coil? If the transformer were 100% efficient, what current would flow through the primary coil when the current in the secondary coil was 0.4 A?
22. A power station generates 500 MW of electrical power which is fed to a transmission line. What current would flow in the transmission line, if the input voltage is 250 kV?