A rod of 20 cm lying along the horizontal East-West direction falls freely from the roof of a building of height 3 m. If the horizontal component of the Earth's magnetic field is 0.36 G over the region, find the magnitude of Induced emf when it reaches the bottom of the building (take $g=10 m / s^2$ at that place)

$0.56 \times 10^{-4} V$

The correct answer is Option (2) → $0.56 \times 10^{-4} V$

The induced emf (ε) in a conductor moving through a magnetic field is -

$ε=B.v.l$

where,

B = Magnetic field

v = Velocity of Rod

L = Length of Rod

and,

$v=\sqrt{2gh}$

$=\sqrt{2×9.8×3}$

$≃7.67m/s$

$∴ε=(0.36×10^{-4})×(7.67)×(0.2)$

$≃5.52×10^{-5}V$