Consider a uniform electric field `E = 3xx10^(3) hat(i) N//C`. (a) What is the flux of this field through a square of 10 cm on a side whose plane is parallel to the yz plane ? (b) What is the flux through the same square if the normal to its plane makes a `60^(@)` angle with the x-axis ?

Explanation

(a)The given electric field intensity is along the positive X-axis. The plane of square is parallel to Y-Z plane, hence normal to this surface is also parallel to X-axis. The electric flux linked with the square can be written as follows:
`phi=vecE. DeltavecS=3xx10^3 xx(0.1)^2xxcos 0^@`
`=30 N m^2//C`
(b)`phi=vecE.DeltavecS=3xx10^3xx(0.1)^2xxcos 60^@`
`=15 N m^2//C`