A) 1A
B) 50 A
C) 0.5 A
D) 5 A
Correct Answer: C
Solution :
Key Idea: Due to changing magnatic field an emf is induced in the coil. From Faradays law of electromagnetic induction, when magnetic flux linked with a circuit changes, an emf is induced in the coil. \[\therefore \] \[\left| e \right|=\frac{d\phi }{dt}=\frac{NA\,dB}{dt}\,(\because \phi =NAB)\] where N is number of turns in the coil, A is area and B is magnetic field. Given \[N=20,\,A=25\,c{{m}^{2}}=25\times {{10}^{-4}}{{m}^{2}}\] \[R=100\,\Omega ,\frac{dB}{dt}=1000\,T/s\] \[\therefore \]Also \[\left| e \right|=IR\] \[\Rightarrow \] \[I=\frac{\left| e \right|}{R}=\frac{NA}{R}\,.\,\,\frac{dB}{dt}\] Putting the given numerical values, we have \[I=\frac{20\times 25\times {{10}^{-4}}}{100}\times 1000\] \[I=0.5\,A\]You need to login to perform this action.
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