Question

Consider a uniform electric field `E=3xx10^(3) 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?

Answer 1

(a) Given `E=3xx10^(3) N//C`
`S=10^(2) cm^(2)=10^(2)xx(10^(-2) m)^(2)=10^(-2) m^(2)`
`theta=0^(@)`
`phi=ES cos theta`
`=3xx10^(3)xx10^(-2)xxcos 0^(@)`
`:. Phi=30 Nm^(2) C^(-1)`
(b) If `theta=60^(@), phi =ES cos theta`
`=3xx10^(3)xx10^(-2)xx cos 60^(@)`
`:. phi =15 Nm^(2) C^(-1)`