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प्रश्न
Name the material of core in (a) an electric bell, (b) electromagnet, (c) a d.c. motor, (d) an a.c. generator and (e) a transformer.
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उत्तर
Soft iron is used in all.
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संबंधित प्रश्न
How will you make an iron bar electromagnet? Draw a diagram showing the polarities of the electromagnet?
State three uses of an electromagnet?
State two factors on which the strength of induced e. m.f. depends.
How does a magnetic field set up by a solenoid change when strength of current in the solenoid is decreased?
Why is soft iron generally used as the core of the electromagnet?
State the energy change that takes’place in 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.
Point out three differences between an electromagnet and a bar (or permanent) magnet.
State and explain Maxwell’s Cork Screw Rule.
(i) A straight wire conductor passes vertically through a piece of cardboard sprinkled with iron filings. Copy the diagram and show the setting of iron filings when a current is passed through the wire in the upward direction and the cardboard is tapped gently. Draw arrows to represent the direction of the magnetic field lines.
(ii) Name the law which helped you to find the direction of the magnetic field lines.
