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प्रश्न
State two advantages of an electromagnet over a bar magnet.
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उत्तर
Electromagnet can produce a strong magnetic field. Its polarity can be changed by reversing the direction of current.
संबंधित प्रश्न
Suppose you are given a long bar magnet and you are asked to break it into four small magnets. Draw diagrams showing the polarities of each broken part.
Describe a simple Experiment to demonstrate that there Exists a magnetic field around a current-carrying conductor.
State the condition when an electric charge can give rise to a magnetic field.
What is a permanent magnet? Give one use of it.
State three factors which govern the speed of rotation of an electric motor.
What energy conversion takes place during the working 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 and the coil is minimum.
What is dynomo (a.c. generator)? State the principle on which it works.
State and explain Maxwell’s Cork Screw Rule.
How does a magnetic field set up by a solenoid change when cross-sectional area of solenoid is increased?
