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प्रश्न
What is a permanent magnet? Give one use of it.
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उत्तर
A permanent magnet is a magnet made from steel such that once magnetized, it does not lose its magnetism easily. Use: It is used in the galvanometer.
संबंधित प्रश्न
State two ways of magnetising an iron piece?
Show with the aid of a diagram how a wire is wound on a U-shaped piece of soft iron in order to make it an electromagnet. Complete the circuit diagram and label the poles of the electromagnet.
State two factors on which the magnitude of an induced e.m.f. in the secondary coils of a transformer depends.
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.
State the position of armature coil relative to the direction of magnetic field, in a D. C. motor when the deflecting couple acting and the coil is minimum.
The primary windings of a step-up transformer are usually made of thicker wire than the secondary. Explain.
State important properties (or characteristics) of magnetic lines of force around a straight conductor.
Point out three differences between an electromagnet and a bar (or permanent) magnet.
State and explain Maxwell’s Cork Screw Rule.
