A) \[B\pi {{r}^{2}}IN\]
B) \[\frac{B{{r}^{2}}I}{\pi N}\]
C) Zero
D) \[\frac{B\pi {{r}^{2}}I}{N}\]
Correct Answer: A
Solution :
Magnetic moment of coil \[=NIA\hat{j}\] \[=NI(\pi {{r}^{2}})\hat{j}\] Torque on loop (coil)\[=\vec{M}\times \vec{B}\] \[=NI\left( \pi {{r}^{2}} \right)B\sin {{90}^{o}}\left( -\hat{k} \right)\] \[=NI\pi {{r}^{2}}B\left( -\hat{k} \right)\]You need to login to perform this action.
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