JEE Main202228 Jul 2022Morning ShiftPhysicsMagnetic Effects of CurrentActual
As shown in the figure, a metallic rod of linear density 0 . 45 kg m - 1 is lying horizontally on a smooth incline plane which makes an angle of 45 ° with the horizontal. The minimum current flowing in the rod required to keep it stationary, when 0 . 15 T magnetic field is acting on it in the vertical upward direction, will be (Use g = 10 m s - 2 )
Options
- A30   A
- B15   A
- C10   A
- D3   A
Correct answer
A. 30   A
Step-by-step solution
For the wire to remain stationary, the net force acting on it should be zero. Balancing the forces along the incline, m g sin 45 ° = I L B cos 45 ° ⇒ I = m L g B ⇒ I = 0 . 45 10 0 . 15 = 30   A