Consider the cylindrical region of the magnetic field shown in the figure. Region I and II have fields directed perpendicularly outward and inward, respectively. Fields are varying with time as
Region I:B1=3B0t
Region II:B2=B0t
Find the ratio r1r2 providing there is no net induced electric field in the region outside the magnetic field.
Note: For a region outside the magnetic field i.e. r>R ∮→E⋅→dl=−dϕdt ⇒E × 2πr=−dϕdt ⇒E=−dϕdt.12πr Therefore, electric field even exists (due to the change in flux inside the region) in the region where magnetic field is not present. |