• # question_answer A circular coil of radius 0.1 m has 80 turns of wire. If the magnetic field through the coil increases from 0 to 2 Tesla in 0.4 sec and the coil is connected to a$11\,\Omega$ resistor, what is the current (in A) through the resistor during the 0.4 sec interval? A) $\left( \frac{8}{7} \right)A$               B) $\left( \frac{7}{8} \right)A$C) $8\,A$                        D) $7\,A$

$e=-N\frac{d\Phi }{dt}=-NA\frac{dB}{dt}=-80\times \frac{22}{7}\times {{(0.1)}^{2}}\left( \frac{2.2}{0.4} \right)$ $I=\frac{e}{R}=80\times \frac{22}{7}\times \frac{{{(0.1)}^{2}}\times 5}{11}=\frac{8}{7}A.$ Hence, the correction option is [b].