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प्रश्न
Fill in the following blank with suitable words:
The magnetic effect of a coil can be increased by increasing the number of ........... increasing the ........... or inserting an ........... core.
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उत्तर
The magnetic effect of a coil can be increased by increasing the number of turnsincreasing the current or inserting an iron core.
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संबंधित प्रश्न
When the current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position. Explain.
Fill in the following blank with suitable words:
If a coil is viewed from one end and the current flows in an anticlockwise direction, then this end is a ........... pole.
Describe some experiment to show that the magnetic field is associated with an electric current.
If the direction of electric current in a solenoid when viewed from a particular end is anticlockwise, then this end of solenoid will be:
(a) west pole
(b) south pole
(c) north pole
(d) east pole
Name one device which works on the magnetic effect of current.
The north pole of a long bar magnet was pushed slowly into a short solenoid connected to a galvanometer. The magnet was held stationary for a few seconds with the north pole in the middle of the solenoid and then withdrawn rapidly. The maximum deflection of the galvanometer was observed when the magnet was ______.
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 magnet is a rest in the coil?
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?
(b) State whether the following statements are true or false:
(i) Magnetic poles exist in pairs.
(ii) Global warming is a desirable aspect of the intensified greenhouse effect.
Name any two appliances which works on the phenomenon of magnetic effect of electric current.
Identify the given figure, write the labels of it.
Why do we cover plug pin holes which are within the reach of children with cellotape or a plastic cover when not in use?
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.
A wire with green insulation is usually the live wire of an electric supply.
Define the magnetic effect of electric current.
A student was asked to perform an experiment to study the force on a current carrying conductor in a magnetic field. He took a small aluminium rod AB, a strong horse shoe magnet, some connecting wires, a battery and a switch and connected them as shown. He observed that on passing current, the rod gets displaced. On reversing the direction of current, the direction of displacement also gets reversed. On the basis of your understanding of this phenomenon, answer the following questions:
- Why does the rod get displaced on passing current through it?
- State the rule that determines the direction of the force on the conductor AB.
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- If the U-shaped magnet is held vertically and the aluminium rod is suspended horizontally with its end B towards due north, then on passing current through the rod from B to A as shown, in which direction will the rod be displaced?
- Name any two devices that use current carrying conductors and magnetic fields.
OR
Draw the pattern of magnetic field lines produced around a current carrying straight conductor held vertically on a horizontal cardboard. Indicate the direction of the field lines as well as the direction of current flowing through the conductor.
A rectangular loop ABCD carrying a current I is situated near a straight conductor XY, such that the conductor is parallel to the side AB of the loop and is in the plane of the loop. If a steady current I is established in the conductor as shown, the conductor XY will ______.
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.
