question_answer

In a coil of resistance \[100\,\Omega ,\] a current is induced by changing the magnetic flux through it as shown in the figure. The magnitude of change in flux through the coil is:     JEE Main Solved Paper-2017

A)  250 Wb                               

B)  275 Wb

C)  200 Wb                               

D)  225 Wb

Correct Answer: A

Solution :

\[q=\frac{\Delta \text{o}|}{R}\] \[\Delta \text{o }\!\!|\!\!\text{ }=\]change in flux \[q=\int_{{}}^{{}}{I\,dt}\] = Area of current-time graph \[=\frac{1}{2}\times 10\times 0.5=2.5\]coloumb \[q=\frac{\Delta \text{o}|}{R}\] \[\Delta \text{o }\!\!|\!\!\text{ =2}\text{.5}\times 100=250\,Wb\]