At a place the value of horizontal component of the earth's magnetic field is $3\times {10}^{-5} \mathrm{Wb}/{\mathrm{m}}^2.$ A metallic rod AB of length 2 m placed in east-west direction, having the end A towards east, falls vertically downward with a constant velocity of 50 m/s. Which end of the rod becomes positively charged and what is the value of induced potential difference between the two ends?

• A

  $\text{ End }\mathrm{A}, 3\times {10}^{-3} \mathrm{mV}$

• B

  End A, 3 mV

• C

  $\text{ End }\mathrm{B}, 3\times {10}^{-3} \mathrm{mV}$

• D

  End B, 3 mV