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)
Answer & explanation
Correct answer: option 2
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,
$v=\sqrt{2gh}$
$=\sqrt{2×9.8×3}$
$≃7.67m/s$
$∴ε=(0.36×10^{-4})×(7.67)×(0.2)$
$≃5.52×10^{-5}V$