A 20 m long horizontal wire extends from North-East to South-West. It is falling down with a speed of 4 m/s horizontally. The horizontal components of the earth's magnetic field is $0.4 × 10^{-4} T$. Find the value of induced current in the wire if the resistance of wire is 2Ω is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 1.6 mA
The induced emf of a given conductor is -
$ε=B.L.v$
$=(0.4×10^{-4})(20)(4)$
$=3.2×10^{-3}V$
$I=\frac{ε}{R}=\frac{3.2×10^{-3}}{2}$ [Using Ohm's law]
$I=1.6mA$