A coil in the shape of a square having 200 turns, with an area of each turn $2.5×10^{-3} m^2$ and a total resistance of 200 Ω, is placed in a uniform magnetic field of 0.5 T, such that the plane of the coil is perpendicular to the magnetic field. The loop is pulled out of the field slowly and uniformly in 1.0 s as shown in the figure. The magnitude of induced current in the coil is:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 1.25 mA
Number of turns in coil (N) = 200
Area of each turn (A) = $2.5×10^{-3}m^2$
Resistance of coil (R) = 200Ω
Magnetic field (B) = 0.5T
Time interval (t) = 1.0s
Change in Magnetic flux, $Δ\phi_{total}=\phi_{initial}-\phi_{final}$
$=(200×0.05×10^{-3}×0.5)-0$
$=0.25Wb$
By faraday's law, the magnetic of induced emf,
$ε=\frac{Δ\phi_{total}}{t}=\frac{0.25}{1}=0.25V$
and,
$I=\frac{ε}{R}$ [By Ohm's law]
$=\frac{0.25}{200}=1.25mA$