A) 12
B) 24
C) 36
D) 48
Correct Answer: B
Solution :
In perpendicular position in uniform magnetic field, magnetic field linked with the each turn of coil \[\text{o}{{\text{ }\!\!|\!\!\text{ }}_{1}}=BA\] On rotating coil through \[{{180}^{o}},\] flux linked \[\text{o}{{\text{ }\!\!|\!\!\text{ }}_{2}}=-BA\] \[\therefore \] Change in magnetic flux \[\Delta \text{o }\!\!|\!\!\text{ }=\text{o}{{\text{ }\!\!|\!\!\text{ }}_{2}}-\text{o}{{\text{ }\!\!|\!\!\text{ }}_{1}}=-2BA.\] \[\therefore \] emf induced in the coil \[e=-N\frac{\Delta \text{o }\!\!|\!\!\text{ }}{\Delta t}\] \[=\frac{2NBA}{\Delta f}\]where N is the number of turns in the coil. The current in the coil \[i=\frac{e}{R}=\frac{2NBA}{R\Delta \Tau }\] \[=\frac{2\times 1200\times 4\times {{10}^{-4}}\times 500\times {{10}^{-4}}}{20\times 0.1}\] \[=2400\times {{10}^{-5}}\] \[=24\times {{10}^{-3}}A\] \[=24\,mA\]You need to login to perform this action.
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