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प्रश्न
Write the answer in your words.
How is an electromagnet made?
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उत्तर
For the construction of an electromagnet, we require an iron nail, a long insulated copper wire, a battery and a switch.
The long, insulated copper wire is first wound on the iron nail. Then the two free ends of the wire are connected to the battery and the switch as shown. Now that the switch is turned on, current flows through the circuit. Due to this flow of current, the insulated copper wire and iron nail act as an electromagnet. Now, if iron pins are brought close to this set-up, they stick to the iron nail.
As soon as the current stops flowing in the circuit, the iron nail loses magnetism and the pins fall off.
Case: Switch open
Case: Switch close
संबंधित प्रश्न
The diagram shows a coil wound around a U shape soft iron bar AB.
1) What is the polarity induced at the ends A and B when the switch is pressed?
2) Suggest one way to strengthen the magnetic field in the electromagnet
3) What will be the polarities at A & B if the direction of current is reversed in the circuit?
Fill in the blanks by writing (i) Only soft iron, (ii) Only steel, (iii) Both soft-iron and steel for the material of core and/or magnet.
Electromagnet ______.
State two factors on which the strength of induced e. m.f. depends.
A straight wire is held vertical and current is passed in it in the upward direction. A compass needle is kept near the wire in north of it. How is the needle deflected? What is the change in the deflection of the needle if the current in wire is reversed?
Describe a simple Experiment to demonstrate that there Exists a magnetic field around a current-carrying conductor.
State the principle of a D. C. motor.
State the position of armature coil relative to the direction of magnetic field, in a D. C. motor when the deflecting couple acting an the coil is maximum.
State the factors, on which depends the magnitude of the force acting on current carrying conductor, when it is kept in a magnetic field perpendicular to it.
Point out three differences between an electromagnet and a bar (or permanent) magnet.
How does a magnetic field set up by a solenoid change when cross-sectional area of solenoid is increased?
