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The magnetic flux through a coil is 4xx10^-4Wb/m^2 at time t = 0. It reduces to 10% of its original value in 't' seconds. If the induced e.m.f. is 0.72mV, then what is the time t? |
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Answer» SOLUTION :`E = (-dphi)/DT = phi_2-phi_1/dt` and `phi_2 = 1phi_1/10` `THEREFORE phi_1-phi_2` = 9phi_1/10` `therefore dt = phi_1-phi_2/e= 9/10xx4xx10^-4//72xx10^-5` = 1/2 = 0.5s |
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