Most Important Selected Qs for JEE AdvancedPhysicsElectromagnetic Induction
Two parallel conducting rails are connected to a source of emf E and internal resistance r. Another conducting rod of length having negligible resistance lies at rest and can slide without friction over the rails. A uniform magnetic field B is applied perpendicular to the plane of the rails. At t=0 , the rod is pulled along the rails by applying a force F . The velocity of the rod is observed to be v=v₀ ( t) then fin
Correct answer
4
Step-by-step solution
Force on the rod F-F_m=m aF- B r (B / V-E)=m aF+ B E r - B^2 ^2 V r = m d V d t solving F=-m V₀ ( t)+ B^2 ^2 r V₀ t- B E r Power expended by force is F V=-m V₀^2 ( t) ( t)+ B^2 ^2 r V₀^2 ^2 t- B E r V₀ t Its average over the cycle is B ^2 ^2 ~V ₀^2 2 r