Advertisements
Advertisements
प्रश्न
For the coil in the diagram below, when the switch is pressed:
(a) what is the polarity of end A?
(b) which way will the compass point then?
Advertisements
उत्तर
When the switch is pressed,
(a) the current will flow in the clockwise direction at end A; therefore, this end will behave like the south pole.
(b) The other end of the coil will behave like the north pole, and because of the repulsive force at the north pole, the compass (or point of the compass) will move away from the coil.
APPEARS IN
संबंधित प्रश्न
When the current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position. Explain.
An electromagnet does not attract a piece of iron.
Do you think an electromagnet can be used for separating plastic bags from a garbage heap? Explain.
The magnetic effect of current was discovered by:
(a) Maxwell
(b) Fleming
(c) Oersted
(d) Faraday
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.
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?
Name any two appliances which works on the phenomenon of magnetic effect of electric current.
Identify the given figure, write the labels of it.
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
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.
______ cells cannot be recharged after use.
A wire with green insulation is usually the live wire of an electric supply.
The figure given below shows the magnetic field around the conductor. Study it and answer the questions:
- What changes are caused by increasing current?
- What do you see when the magnetic needle is kept a little away from the wire?
- In the second part of the figure, the iron filings arrange themselves in a circular manner around the wire. Why does this happen?
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.
