question_answer

A rectangular loop carrying a current i is placed in a uniform magnetic field B. The area enclosed by the loop is A. If there are n turns in the loop, the torque acting on the loop is given by                                                   [MP PMT 1994]

A)            \[ni\,\overrightarrow{A}\times \overrightarrow{B}\]         

B)            \[ni\,\overrightarrow{A}\cdot \overrightarrow{B}\]

C)            \[\frac{1}{n}(i\overrightarrow{A}\times \overrightarrow{B})\]       

D)            \[\frac{1}{n}(i\overrightarrow{A}\cdot \overrightarrow{B})\]