Question

A conducting bar of length , moves to the right on two frictionless rails. A uniform magnetic field directed into the page has a magnitude of 0.300 T. Assume R = 9.00 Ohm and , length (l) = 0.350 m. At what constant speed should the bar move to produce an 8.50- mA current in the resistor?

Answer 1

0.7286 m/s

Step-by-step explanation:

B = 0.3 T, R = 9 ohm, l = 0.350 m, i = 8.5 m A = 8.5 x 10^-3 A

Let the speed is v.

The motional emf is given by

e = B v l

i x R = B v l

8.5 x 10^-3 x 9 = 0.3 x v x 0.350

v = 0.7286 m/s