the inner circles are shaded darker :)
inside our rod the Lorentz force is acting on the free electrons: |dw:1434439163697:dw|
at the equilibrium thos forces, the lorentz force and the electrostatic force have the same magnitude, so we can write: \[\Large eE = evB\] and then: \[\Large V = vBL\] being L the length of the rod, and V the emf
ok! what do we plug in? :/
\[V = vBL = 20 \times 0.02 \times 1.2 = ...volts\]
we get 0.48! so choice B is the solutoin?
yes! that's right!
yay!thanks!! okay, last one!!:)