Question 180: Electromagnetic Induction

Question

Magnetic flux (in weber) in a closed circuit of resistance 20 $$\Omega$$ varies with time t(s) at $$\phi$$ = 8t2 $$-$$ 9t + 5. The magnitude of the induced current at t = 0.25 s will be ____________ mA.

Accepted Answer

$$R = 20\,\Omega $$
$$\phi  = 8{t^2} - 9t + 5$$
$$\varepsilon  = \left| { - {{d\phi } \over {dt}}} ight| = |16t - 9| = |16(0.25) - 9| = 5$$
$$i = {\varepsilon  \over R} = {5 \over {20}} = 0.25\,A = {{0.25} \over {{{10}^3}}} 	imes {10^3}\,A = 250\,mA$$

Electromagnetic Induction

Magnetic flux (in weber) in a closed circuit of resistance 20 $\Omega varies with time t(s) at \phi = 8t2 -$ 9t + 5. The magnitude of the induced current at t = 0.25 s will be ____________ mA.

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