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A circular coil of radius 10cm, 500 turns and resistance 2Omega is placed with its plane perpendicular to the horizontal component of the earth's magnetic field. It is rotated about its vertical diameter through 180^(@)" in "0.25s. Estimate the magnitudes of the emf and current induced in the coil. Horizontal component of the earth's magnetic field at the place is 3.0 xx 10^(-5)T. |
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Answer» Solution :INITIAL flux through the coil, `phi_(B_("initial"))=BA cos theta` `=3.0xx10^(-5)xx(pixx10^(-2))xxcos 0^@` `=3pixx10^(-7)Wb` Final flux after the rotation. `phi_(B_("final"))=3.0xx10^(-5)xx(pixx10^(-2))xxcos 180^(@)` `=-3pixx10^(-7)Wb` THEREFORE, estimated value of INDUCTED emf is `epsi=N(DELTAPHI)/(Deltat)=500xx (6pixx10^(-7))//0.25` `=3.8xx10^(-3)V` `I=epsi//R=1.9xx10^(-3)A` Note that the magnitudes of `epsi` and I are the estimated values. |
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