A) \[1.15\,\mu J\]
B) \[9.1\,\mu J\]
C) \[4.55\,\mu J\]
D) \[2.3\,\mu J\]
Correct Answer: B
Solution :
\[W=MB(cos{{\theta }_{1}}-cos{{\theta }_{2}})\] When it is rotated by angle \[{{180}^{o}}\]then \[W=2MB\] \[W=2(NIA)B\] \[=2\times 250\times 85\times {{10}^{-6}}[1.25\times 2.1\times {{10}^{-4}}]\times 85\] \[\times {{10}^{-2}}\] \[=9.1\,\mu J\]You need to login to perform this action.
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