NTA Abhyas JEE Main2020PhysicsElectromagnetic InductionPractice
Consider a thin metallic sheet perpendicular to the plane of the paper moving with speed v in a uniform magnetic field B going into the plane of the paper (see figure). If charge densities σ 1 and σ 2 are induced on the left and right surfaces respectively of the sheet, then (ignore fringe effects)
Options
- Aσ 1 = - ϵ 0 vB 2 ,   σ 2 = ϵ 0 vB 2
- Bσ 1 = ϵ 0 vB ,   σ 2 = - ϵ 0 vB
- Cσ 1 = ϵ 0 vB 2 ,   σ 2 = - ϵ 0 vB 2
- Dσ 1 = σ 2 = ϵ 0 vB
Correct answer
B. σ 1 = ϵ 0 vB ,   σ 2 = - ϵ 0 vB
Step-by-step solution
σ 1 = - σ 2 [due to magnetic force] E = σ ε 0 = vB σ = ε 0 vB