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A circular copper disc 10 cm in radius rotates at 20pi rad/s about an axis through its centre and perpendicular to the disc. A uniform magnetic field of 0.2 T acts perpendicular to the disc. (i) Calculate the potential difference developed between the axis of the disc and the rim. (ii) What is the induced current if the resistance of the disc is 2Omega? |
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Answer» Solution :Here radius `r = 10 cm = 0.1 m, omega = 20pi rad/s and B = 0.2 T` `THEREFORE` Potential difference between the axis of the disc and the rim `V = 1/2 Br^(-2) omega =1/2 2 xx (0.1)^(2) xx 20pi= 6.28 xx 10^(-2)V`. (ii) As RESISTANCE `R = 2OMEGA`, hence induced current `I = V/R = (6.28 xx 10^(-2))/2=3.14 xx10^(-2)A.` |
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