Question

A rectangular coil of $n$ turns is perpendicular to a uniform magnetic field. If the field is reversed in a short time interval of t, then find the value of $n$ given the charge flowing through the wire is independent of time.

• A. 1
• B. - 1
• C. zero
• D. 2

Answer 1

Answer: (C)

zero

$Emf=\frac{2nBA}{t}$
$i=\frac{Emf}{R}=\frac{2nBA}{Rt}$
$q=it=\frac{2nBA}{R}$
So,Charge is independent of time and hence , $n=$0
Where, n is number of turns in coil, B is magnetic field. A area of rectangular coil, R is resistance of coil and t is time