In the arrangement shown a conducting bar of negligible resi

In the arrangement shown, a conducting bar of negligible resistance slides along horizontal, parallel, frictionless conducting rails connected as shown to a 2.0-Q resistor. A uniform 1.5-T magnetic field is perpendicular to the plane of the paper. If L = 60 cm, at what rate is thermal energy being generated in the resistor at the instant the speed

Solution

P = [B² L² / R] * v²

= [1.5² * 0.6² / 2] * 4.2²

= 7.14 W