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Question
Explain the magnetic field created by a current around a conductor from the figure.
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Solution
- Consider a circuit connected as shown in the figure.
- A cardboard is placed around a thick copper wire. A magnetic needle is used to check the magnetic field around the wire.
- When a large current flows through the thick wire, the magnetic needle shows deflection. At different points on the cardboard, the needle points in different directions.
- When joined the directions shown by the needle, the lines formed indicate that the magnetic field produced around a current-carrying conductor is in the form of concentric circles.
- The deflection in the needle changes according to the current in the conductor. For a given current, if we move the compass needle away from the wire, its deflection decreases.
- The direction of the magnetic field formed around the conductor depends on the direction of the current and is given by the right-hand thumb rule.
- If the thumb of the right hand indicates the direction of the current then, the curled fingers indicate the direction of the magnetic field formed.
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