Question

state Gauss Theorem apply this to obtain the expression for the electric field intensity at a point due to an infinitely long thin uniformly charged straight wire

Answer 1

Gauss Theorem is defined such that, the electric flux through a closed surface is equal to surface integral of electric field in that closed surface.

• φ = $\int\limits^0_s {E} \, da$

• Where flux is defined as φ = q/ε0
• Consider a Gaussian cylindrical surface of radius z and length L such that wire is the central axis.

• Gauss law

                      $\int\limits^0_s {E} \, da$  = q/ε0

               E*2*π*z *L  = (λL)/ ε0

                              E  = λ/2*π*ε0*z