Magnetic Effects of Electric Current QUESTIONS

Magnetic Effects of Electric Current

QUESTIONS

1. Why does a compass needle get deflected when brought near a bar magnet?
2. Draw magnetic field lines around a bar magnet.
3. List the properties of magnetic lines of force.
4. Why don’t two magnetic lines of force intersect each other?
5. Consider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right-hand rule out the direction of the magnetic field inside and outside the loop.
6. The magnetic field in a given region is uniform. Draw a diagram to represent it.
7. Choose the correct option: The magnetic field inside a long straight solenoid carrying current

(a) is zero. (b) decreases as we move towards its end;

(c) increases as we move towards its end; (d) is the same at all points.

8. Which of the following of proton can change while it moves freely in a magnetic field? (There may be more than one correct answer.)
9. A positively-charged particle (alpha-particle) projected towards west is deflected towards north by a magnetic field. The direction of magnetic field is

(a) towards south (b) towards east (c) downwards (d) upward.

10. State Fleming’s left-hand rule.
11. What is the principle of an electric motor?
12. What is the role of the split ring in an electric motor?
13. Explain different ways to induce current in a coil.
14. State the principle of an electric generator.
15. Name some sources of direct current.
16. Which sources produce alternating current?
17. Choose the correct option:

A rectangular coil of copper wires is rotated in magnetic field. The direction of the induced current changes once in each

(a) two revolutions (b) one revolution

c half revolution (d) one-forth revolution

18. Name two safely measures commonly used in electric circuits and appliances.
19. An electric oven of 2kW power rating is operated in a domestic electric current (220 V) that has a current rating of 5 A. What result do you expect? Explain.
20. What precaution should be taken to avoid the overloading of domestic electric circuits?
21. What is the function of an earth wire? Why is it necessary to earth metallic appliances?
22. What is the function of an earth wire? Why is it necessary to earth metallic appliances?
23. When does an electric short circuit occur?
24. Explain the underlying principle and working of an electric generator by drawing a labelled diagram. What is the function of brushes?
25. State the rule to determine the direction of a (i) magnetic field produced around a straight conductor carrying current, (ii) force experienced by a current-carrying straight conductor placed in a magnetic field which is perpendicular to it, and (iii) current induced in a coil due to its rotation in a magnetic field.
26. Two circular coils A and B are placed closed to each other. If the current in the coil A is changed, will some current be induced in the coil B? Give reason.
27. A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is (i) pushed into the coil, (ii) withdraw from inside the coil, (iii) held stationary inside the coil?
28. Name some devices in which electric motors are used.
29. Draw a labelled diagram of an electric motor. Explain its principle and working. What is the function of a split ring in an electric motor?
30. Think you are sitting in a chamber with your back to one wall. An electron beam, moving horizontally from back wall towards the front wall, is deflected by a strong magnetic field to your side. What is the direction of magnetic field?
31. When is the force experienced by a current carrying conductor placed in a magnetic field is largest                                                                                                               Read more topics ...
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