JEE Main202310 Apr 2023Morning ShiftPhysicsElectromagnetic InductionActual
A 1   m long metal rod X Y completes the circuit as shown in figure. The plane of the circuit is perpendicular to the magnetic field of flux density 0 . 15   T . If the resistance of the circuit is 5   Ω , the force needed to move the rod in direction, as indicated, with a constant speed of 4   m   s - 1 will be _______ 10 – 3   N .
Correct answer
0
Step-by-step solution
The force on the rod is given by F = i l B ⇒ F = B v l R × l B ⇒ F = B 2 l 2 v R       . . . ( i ) The data given is R = 5   Ω l = 1   m v = 4   m   s - 1 B = 0 . 15   T Substituting the values in equation (i) F = 0 . 15 2 × 1 2 × 4 5 = 18 × 10 - 3   N