JEE Advanced 2020 Full Test 7 Paper 1

Two parallel vertical metallic rails AB and CD are separated by 1 m. They are connected at the two ends by resistances R1 and R2 as shown in the figure. A horizontal metallic bar PQ of mass 0.2kg sides with out friction, vertically down the rails under the action of gravity. There is uniform horizontal magnetic field of 0.6T, which is perpendicular to plane of the rails. It is observed that when the terminal velocity attained, the power dissipated in resistance R1 and R2 are 0.76W and 1.2W, respectively. Find the terminal velocity ( in m∕s) of the bar. (Take g=9.8m∕s2)