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प्रश्न
A cylindrical bar magnet is rotated about its axis (Figure). A wire is connected from the axis and is made to touch the cylindrical surface through a contact. Then
पर्याय
a direct current flows in the ammeter A.
no current flows through the ammeter A.
an alternating sinusoidal current flows through the ammeter A with a time period T = 2π/ω.
a time varying non-sinosoidal current flows through the ammeter A.
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उत्तर
A cylindrical bar magnet is rotated about its axis (Figure). A wire is connected from the axis and is made to touch the cylindrical surface through a contact. Then no current flows through the ammeter A.
Explanation:
The phenomenon of electromagnetic induction is used in this problem. Whenever the number of magnetic lines of force (magnetic flux) passing through a circuit changes (or a moving conductor cuts the magnetic flux) an emf is produced in the circuit (or emf induces across the ends of the conductor) is called induced emf. The induced emf persists only as long as there is a change or cutting of flux.
When cylindrical bar magnet is rotated about its axis, no change in flux linked with the circuit takes place, consequently no emf is induced and hence, no current flows through the ammeter A. Hence the ammeter shows no deflection.
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संबंधित प्रश्न
Ram is a student of class X in a village school. His uncle gifted him a bicycle with a dynamo fitted in it. He was very excited to get it. While cycling during night, he could light the bulb and see the objects on the road. He, however, did not know how this device works. he asked this question to his teacher. The teacher considered it an opportunity to explain the working to the whole class.
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