Take a strong cylindrical electromagnet connected to AC source and place a light metallic disc at the top of it. When the current is switched 'on', the disc is thrown up in the air. a. Why does the disc go up? b. How is the repulsive force produced?

Take a strong cylindrical electromagnet connected to AC source and pla

1.	Take a strong cylindrical electromagnet connected to AC source and place a light metallic disc at the top of it. When the current is switched 'on', the disc is thrown up in the air. a. Why does the disc go up? b. How is the repulsive force produced?
Answer» Solution :a. Induced CURRENTS are produced in the disc which acts in such a manner that it OPPOSES the increase of magnetic flux through it. As a result the disc is thrown up. b. When the circuit is switched on, the current starts growing through the solenoid. As the current grows, the magnetic lines along the axis of the solenoid and HENCE magnetic flux through the disc ALSO increases from zero to some finite value. Induced currents are produced in the disc which opposes the increase of magnetic flux through it. Hence the disc is thrown up.

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Take a strong cylindrical electromagnet connected to AC source and place a light metallic disc at the top of it. When the current is switched 'on', the disc is thrown up in the air. a. Why does the disc go up? b. How is the repulsive force produced?

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