Question

A point charge of 2C is placed at centre of Faraday cage in the shape

of cube with surface of 9 cm edge. The number of electric field lines

passing through the cube normally will be​

Answer 1

$\huge \underline \green{\sf{ Answer :- }}$

• According to Gauss's theorem of static electricity the net flux through the closed surface( of any shape and size)is Q/eo. Here, Q is net charge enclosed by the surface and eo is electric permittivity of the space.

• Here, charged enclosed by the given closed surface is

• Q=2 microCoulomb=2x10^-6C.

• eo=8.85x10^-12 F/m.
• Therefore, net flux asked for is =(2x10^-6)C/(8.85x10^-12)F/m=2.26x10^-7 Cm/F or (N/C)m^2

Answer 2

The net electric flux through the surface is $2..26*10^{5}Nm^{2}C^{-1}$

Explanation:

Net electric flux(Фnet)through the cubic surface is given by,

ФNet$=\frac{q}{E_{0}}$

$E_{0}=$Permittivity of free space

$=8.854*10^{-12}N^{-1}C^{2}m^{-2}$

q=Net charge contained inside the cube =$2.0$

$uc=2*10^{-6}C$

ФNet=$\frac{2*10^{6}}{8.854*10^{12}}$

$=2.26*10^{5}Nm^{2}C^{-1}$