Question

The figure shows four wire loops, with edge lengths of either $L$ or $2L.$ All four loops will move through a region of uniform magnetic field $\overset{ \rightarrow }{B}$ (directed out of the page) at the same constant velocity. Rank the four loops according to the maximum magnitude of the $e.m.f$ induced as they move through the field, greatest first

• A. $\left(e_{c} = e_{d}\right) < \left(e_{a} = e_{b}\right)$
• B. $\left(e_{c} = e_{d}\right)>\left(e_{a} = e_{b}\right)$
• C. $e_{c}>e_{d}>e_{b}>e_{a}$
• D. $e_{c} < e_{d} < e_{b} < e_{a}$

Answer 1

Answer: (B)

$EMF$ induces across the length of the wire which cuts the magnetic field.
(Length of $c=$ Length of $d\left.>$ (Length of $a=b\left..$ . So $\left(e_{c} = e_{d}\right)>\left(e_{a} = e_{b}\right)$