Question

A man 1.80 m tall walks at 2.00m/s perpendicular to a horizontal magnetic field of 5.0 T; that is, he walks between the pole faces of a very big magnet. Given that his body is full of conducting fluids, estimate the potential difference induced between his head and feet.

I think it's Vind=wvBcos(theta)
=(1.80m(2.00m/s)(5.0T))
= 18 V

Answer 1

That is correct. An induced voltage difference V/L develops across his body that opposes the magnetic force vB per charge q. Thus V = LvB, if he walks in a direction across the B field lines, with his body length perpendicular to the field and motion directions