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The Galaxy Education System
S. N. Kansagra School
Sub: Physics
Class: X
Chapter 10 – Electro Magnetism
Assignment
1. What were the observations made by Oersted is his experiment?
2. What is the shape of magnetic field lines around a straight current carrying conductor?
3. How can we find the direction of magnetic field due to a straight current carrying conductor?
4. What is the shape of magnetic field lines around a circular current carrying conductor?
5. State right hand thumb rule.
6. What is a Solenoid?
7. Show with the help of a diagram that a current carrying solenoid is similar to a bar magnet.
8. Give the factor on which, magnetic field produced by a carrying solenoid depends.
9. Name the rule used to find the direction of force on a current carrying conductor.
10. Name the factor on which force acting on a current carrying conductor depends.
11. What is meant by electromagnetic induction?
12. State Faraday’s first law of electromagnetic induction.
13. state Faraday’s second law of electromagnetic induction.
14. What are the factors on which the strength of induced current depends?
15. State the rule which you use to find the direction of induced current.
16. Give the direction of induced current in the following figure.
S
N
N
S
(b)
(a)
17. What is the principle on which an electric motor works?
18. What is the function of armature coil in an electric motor (dc)?
19. What is the function of battery in a dc motor?
20. Name two types of electric generators.
21. How is alternating current different from direct current?
22. What is the principle on which a dc generator works?
23. Explain Oersted’s experiment.
24. Explain the right hand thumb rule and cork screw rule to find the magnetic field due to a current
carrying conductor.
25. What is the nature of magnetic field produced by a straight current carrying conductor? Explain
with the help of an experiment.
26. What is the nature of magnetic field produced by a current carrying circular coil? Explain with
the help of an experiment.
27. What is a solenoid? Explain with the help of a figure how a solenoid behaves like a bar magnet.
28. What are the factors on which the magnetic field due to a current carrying solenoid depends?
29. Why does a magnetic needle deflect when brought close to a current carrying conductor?
Explain the rule to find the direction of force on a current conductor.
30. State Faraday’s Laws of electromagnetic induction.
31. Explain Fleming’s right hand rule to find the direction of induced current and give to direction
of current in the following figures. (magnetic field directed inwards)
32. What is an electric motor? On what principle does an electric motor work? Do ac motor and dc
motor work on the same principle?
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33. Explain the functions of : (a) Commutator (b) brushes.
34. What is an electric generator? Name the kinds of electrical generators.
35. Differentiate between ac and dc along with the graph.
36. Explain the construction of dc generator.
37. Check the following statements. Write true or false against each:
1. Like magnetic poles attract each other; unlike poles repel.
2. If you strike a sharp edge of a metallic knife against the north pole of a bar magnet, it will
induce a north pole.
3. The magnetic field produced by a current in a straight wire has no poles.
4. An electric generator is a device that converts electrical energy into mechanical energy.
38. The phenomenon of electromagnetic induction is:
a) The process of charging a body.
b) The process of generating a magnetic field due to current passing through a coil.
c) Producing induced current in a coil by relative motion between a magnet and a coil.
d) The process of rotating a coil of an electric motor.
39. A device used for producing current is :
1) generator 2) voltmeter 3) ammeter
4) galvanometer
40. What are magnetic field lines? How is the direction of magnetic field at a point determined?
Mention two important properties of magnetic field lines.
41. Draw a rough sketch of the pattern of the field lines due to
1) current flowing into a circular coil and 2) solenoid carrying current.
42. State the rule to determine the direction of
1. Magnetic field produced around a current carrying conductor.
2. Force experienced by a straight conductor carrying current placed in a magnetic field which
is perpendicular to it.
3. Current induced in a circuit by the changing magnetic flux due to the motion of a magnet.
43. On what factors does the force experienced by a current carrying conductor placed in a uniform
magnetic field depend?
44. Explain the principle and working of an electric motor with the help of a diagram. What is the
function of the split ring commutator?
45. A coil of copper wire is connected to a galvanometer. What would happen if a bar magnet were
1. Pushed into the coil with its north pole entering first.
2. Pulled out of the coil
3. Held stationary inside the coil.
46. Draw a labeled diagram to explain the principle underlying the working of an electric generator.
47. What is the greatest disadvantage with a suspended-type moving coil galvanometer?
48. If the length of the suspension wire is increased does the sensitivity of a moving coil
galvanometer increase or decrease?
49. If a mirror of greater radius of curvature replaces the mirror of a moving coil galvanometer, does
the sensitivity of the galvanometer increase of decrease?
50. Why are the pole pieces of a galvanometer made concave?
51. Why it is more economical to transmit electrical energy at high voltage and low current?
52. In a transformer there is no transfer of charge from the primary to the secondary. How then is
the power transferred?
53. Why can’t we use the ordinary moving coil galvanometer for measuring ac current and voltage?
54. Why should the core of a transformer be laminated?
55. What should be the characteristic of the material, which forms the core of a transformer?
56. Can a transformer work when it is connected to a dc source?
57. What is an electromagnet? What do you know about the simplest form of an electromagnet?
58. Why does the element of an electric heater become red hot whereas the connecting wires are
cold?
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59. Why is soft iron generally used as the core of the electromagnet?
60. What is a permanent magnet? Give one use of it.
61. State two advantages of an electromagnet over a permanent magnet.
62. Why is soft iron preferred to be used as the core of the electromagnet of an electric bell?
63. State two ways for making a galvanometer sensitive to small currents.
64. State two differences between, pivoted and suspended type galvanometers.
65. Draw a properly labeled diagram of a simple alternating current generator.
66. What energy conversion takes place in a generator?
67. Name the principle on which dynamo is based.
68. What is the magnitude of the emf induced in the coil when its plane becomes parallel to the
magnetic field?
69. State advantages of an electromagnet over a permanent magnet.
70. State four factors on which the strength of electromagnet depends.
71. A transformer lowers emf from 220V to 15 V. If the number of turns in primary are 3520, how
many turns are in secondary coil.
72. A transformer lowers emf from 220 V to 15 V. If 400 W power is given in primary. Calculate:
(i) the current in primary coil and (ii) the current in secondary coil.
73. When a current carrying solenoid is freely suspended, it rests along a particular direction. Why
does this happen?
74. Describe the construction and working of a simple step-up transformer.
75. Name the principle on which the functioning of a transformer depends?
76. What is the function of a step-up transformer?
77. Can a transformer work when it is connected to a dc source?
78. The diagram below shows schematically part of a step-down transformer. Draw the complete
diagram in your answer sheet.
79. Diagram below shows a circuit containing a coil wound over a long and thin hollow cardboard
tube. Copy the diagram (i) show the polarity acquired by each face of the solenoid. (ii) Draw the
magnetic field lines of force inside the coil and also show their direction (iii) Mention two
methods to increase the strength of the magnetic field inside the coil.
80. a. Draw a neat labeled diagram, of an ac generator.
b. What is the magnitude of emf included in the coil when its plane becomes parallel to the
magnetic field.
81. The following diagram shows two straight wires carrying current. Copy the diagram and draw
the pattern of lines of force around them and make their directions.
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82. State two ways of increasing the speed of a dc motor.
83. State the energy transformations taking place in the following (1) electric cell and (2) electric
generator.
84. a. Draw a labeled diagram, of the device you would use to transform 200 V ac to 15 V ac.
b. What is the name of this device?
85. What is an electromagnet? State two ways in which, the strength of an electromagnet can be
increased.
86. State two characteristics of a primary coil of a step-up transformer when compared to the
secondary coil.
87. With reference to a dc motor state (i) the energy change that takes place and (ii) the principle on
which it operates.
88. Draw a representative diagram of a dc motor. Label the following in your diagram (i) The field
magnet (ii) the armature (iii) Commutator and (iv) Brushes. What is the energy changes
involved in this case?
89. Draw a sketch of an electric bell with electrical connections and label the main parts. Why is the
armature made of soft iron and not steel?
90. The diagram below shows a coil connected to a center zero galvanometer G. The galvanometer
shows a deflection to the right when the N pole of a powerful magnet is moved to the right as
shown. (i) Explain why the deflection occurs in the galvanometer. (ii) Does the direction of
current in the coil appear clockwise or anticlockwise when viewed from end A? (iii) State the
observation in g when the coil is moved away from N. (iv) State the observation in G when, both
coil and the magnet, are moved to the right at the same speed.
91. Draw a labelled diagram to show the various components of a step-down transformer.
92. State the main difference between a step-up and step-down transformer.
93. Explain briefly how a magnet can be demagnetized using an alternating current.
94. State two ways by which the emf in an ac generator can be increased.
95. state the energy change which takes place when a magnet is moved inside a coil having
galvanometer at its ends. Name this phenomenon.
96. State the function of a split ring in a dc motor.
97. Mention two reasons why a soft iron core is used within the coil of a moving coil galvanometer.
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