A) MB
B) 2MB
C) \[\frac{MB}{2}\]
D) Zero
Correct Answer: B
Solution :
Work done in rotating the dipole \[{{\operatorname{W}}_{{{\theta }_{1}}}}- {{W}_{{{\theta }_{2}}}}= MB \left[ cos{{\theta }_{1}}-cos{{\theta }_{2}} \right]\] Initially dipole is in stable position \[9=0{}^\circ \] \[{{\operatorname{U}}_{1}}=-MB\,\,cos0{}^\circ =-MB\] \[{{\operatorname{U}}_{2}}=-MB\,cos\,\,180{}^\circ =MB\] \[{{\operatorname{W}}_{ext}} \left( We rotate it \right) = {{U}_{2}}-{{U}_{1}} = 2MB\]You need to login to perform this action.
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