Monday, June 10, 2013

Magnetic Effects of Electric Current - CBSE Board Test Questions for class 10

Central Public School,Samastipur and Sadhana Devi Vidyapith Assignment SA-1
Chapter: Magnetic Effects of Electric Current
Section-A [1marks]
1. What does the direction of thumb indicate in the right-hand thumb rule?
2. What is the frequency of alternating current in India?
3. How will you use a solenoid to magnetize a steel bar?
4. An alternating electric current has a frequency of 50 Hz. How many times does it change its direction in one second?
5. Name devices which produce: (i) alternating current, (ii) direct current.
6. Name the physicist who discovered the magnetic effect of the electric current.
7. A straight copper conductor is held parallel to the axis of a freely suspended magnetic needle such that the conductor is under the needle and the current is flowing from south to north. In which direction the north of magnetic needle will move?
8. If a copper conductor carrying a current is held in north-south direction, in which direction will its magnetic field act?
9. Why does the strength of electromagnet increase, when its soft iron core is laminated?
10. Why does a conductor carrying current experiences force when held in a magnetic field at right angles to it?
Section-B [2marks]
11. What will be the frequency of an alternating current, if its direction changes after every 0.01 s?
12. What is a solenoid? Draw the pattern of magnetic field lines of a solenoid through which a steady current flows.
13. A coil of insulated wire is connected to a galvanometer. What would be seen if a bar magnet with its south pole towards one face of the coil is:
(a) Moved quickly towards it? (b) Moved quickly away from it? (c) placed near its one face?
(d) Name the phenomena involved.14. No two magnetic field lines can intersect each other. Explain.
15. Two circular coils A and B are placed close to each other. If the current in the coil A is changed, will some current be induced in the coil B? Give reasons.
Section- C [3marks]
16.What happens to the deflection of the compass needle placed at a point near current carrying straight conductor
(a) if the current is increased,
(b) if the direction of current in the conductor is changed,
(c) if compass is moved away from the conductor?
17. State Fleming’s Right hand rule. Give one application of this rule. What is SI unit of induced current?
18. What is an electric fuse? What result do you expect if someone operates an electric heater of power rating 2 kW, 220 V in a domestic electric circuit. What has a fuse of current rating of 5A? Justify your answer.
19. Why does a current carrying conductor kept in a magnetic field experience force? On what factors does the direction of this force depend? Name and state the rule used for determination of direction of this force.

20. With the help of a neat diagram describe how you can generate induced current in a circuit.
21.Instruction: Read the clues given below and fill up the blocks with appropriate word/term to compete the crossword puzzle given below: One 'word' has been done for you.
The Clues
Across:
3 This principle is useful in solar cooker but can be harmful on earth (5, 5, 6)
5 Element used to make solar cells
6 A black surface ____________ heat.
7 This fossil fuel mode industrial revolution possible
8 A green house gas
10 High rise structures constructed on rivers to produce hydro electricity.
Down:
1. Its construction, on River Ganga, was opposed
2. Clean Fuel (abbreviation)
3. Bio-gas is commonly called
4. Nuclear power generation is based on this process
9. This energy is converted to electrical energy in a thermal power plant