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A steady current $i$ flows in a small square loop of wire of side $L$ in a horizontal plane. The loop is now folded about its middle such that half of it lies in a vertical plane. Let $\overrightarrow {{\mu _1}} $ and $\overrightarrow {{\mu _2}} $ respectively denote the magnetic moments due to the current loop before and after folding. Then
  • A$\overrightarrow {{\mu _2}} = 0$
  • B$\overrightarrow {{\mu _1}} $ and $\overrightarrow {{\mu _2}} $ are in the same direction
  • C$\frac{{|\overrightarrow {{\mu _1}} |}}{{|\overrightarrow {{\mu _2}} |}} = \sqrt 2 $
  • D$\frac{{|\overrightarrow {{\mu _1}} \,|}}{{|\overrightarrow {{\mu _2}} |}} = \left( {\frac{1}{{\sqrt 2 }}} \right)$
IIT 1993, Diffcult
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