Q.
A hollow cylinder has a charge q coulomb within it. If ϕ is the electric flux, in unit of Vm, associated with the curved surface B, the flux linked with the plane surface A, in unit of Vm, will be
Apply Gauss's law to calculate the charge associated with plane surface A.
Gauss's law states that the net electric flux through any closed surface is equal to the net charge inside the surface divided by ε0.
i.e., ϕtotal =ε0q
Let electric flux linked with surfaces A,B and C are ϕA,ϕB and ϕC, respectively. That is ϕtotal =ϕA+ϕB+ϕC
Since, ϕC=ϕA ⇒2ϕA+ϕB=ϕtotal =ε0q
or ϕA=21(ε0q−ϕB)
But ϕB=ϕ (given)
Hence, ϕA=21(ε0q−ϕ)