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प्रश्न
How should the electric lamps in a building be connected so that the switching on or off in a room has no effect on other lamps in the same building?
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उत्तर
The electric lamps in a building should be connected in parallel so that the switching on or off in a room has no effect on other lamps in the same building.
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संबंधित प्रश्न
Describe some experiment to show that the magnetic field is associated with an electric current.
The direction of current flowing in the coil of an electromagnet at its two ends X and Y are as shown below:
What is the polarity of end X?
What is the polarity of end Y?
Name and state the rule which you have used to determine the polarities.
Name one device which works on the magnetic effect of current.
Which way does the wire in the diagram below tend to move?
A coil is connected to a galvanometer. When the N-pole of magnet is pushed into the coil, the galvanometer deflected to the right. What deflection, if any, is observed when:
the N-pole is removed?
A coil is connected to a galvanometer. When the N-pole of magnet is pushed into the coil, the galvanometer deflected to the right. What deflection, if any, is observed when:
the S-pole is inserted?
In the Activity shown below, how do we think the displacement of rod AB will be affected if
- current in rod AB is increased
- a stronger horse-shoe magnet is used
- length of the rod AB is increased?
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Observe the following diagram and choose the correct alternative:
(b) State whether the following statements are true or false:
(i) Magnetic poles exist in pairs.
What is that instrument which can detect the presence of electric current in a circuit?
In the arrangement shown in Figure there are two coils wound on a non-conducting cylindrical rod. Initially the key is not inserted. Then the key is inserted and later removed. Then
A magnetic compass shows a deflection when placed near a current carrying wire. How will the deflection of the compass get affected if the current in the wire is increased? Support your answer with a reason.
Paheli does not have a night lamp in her room. She covered the bulb of her room with a towel at the night to get dim light. Has she taken the right step? Give one reason to justify your answer.
Boojho made an electromagnet by winding 50 turns of wire over an iron screw. Paheli also made an electromagnet by winding 100 turns over a similar iron screw. Which electromagnet will attract more pins? Give reason.
What are MCBs? How do they work?
A wire with green insulation is usually the live wire of an electric supply.
Using an electromagnet, you can make a working model of a railway signal as shown in figure.
Make four electromagnets with 20, 40, 60 and 80 turns. Connect them one by one to a battery of 2 cells. Bring the electromagnet near a box of pins. Count the number of pins attracted by it. Compare the strengths of the electromagnets.
