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| Numerical - 06 |
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| 06. The core of a toroid having 3000 turns has inner and outer radii of 11 cm and 12 cm respectively. The magnetic field in the core for a current of 0.70 A is 2.5 T. What is the relative permeability of the core? |
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| Suggested solution: |
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| The magnetic field in the empty space enclosed by the windings of the toroid is given by |
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| Where n is the number of turns per unit length and I is the current. |
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| If the space is filled by a core of permeability m then equation (1) is rewritten as under. |
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| Now, B=2.5 tesla, I=0.70 ampere, |
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| mean radius=11.5cm=11.5x10-2 m |
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| Here, we have ignored the variation of B across the cross-section of the toroid and taken the radius of the toroid to be mean of inner and outer radii. |
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