Given a uniform electric field `E=2xx10^(3)hati N//C` find the flux of this field through a square of side 20cm, whose plane is parallel to the y-z plane. What would be the flux through the same square, if the plane makes an angle of `30^(@)` with the x axis?

Explanation

When the plane is paralled to the y-z plane :
`phi=vecEvecA" here, " vecE=2xx10^(3)hati`
`vecE=2xx10^(3)hati N//CA`
`A=20xx20xx10^(-4)=4xx10^(-2)hati m^(2)`
`therefore phi=2xx10^(3)hat i. 4xx10^(-2)hati`
`rArr" "phi=80 " weber"`
When the plane makes a `30^(@)` angle with the x-axis the area vector makes a `60^(@)` angle with the x-axis.
`phi=vecEvecA rArr phi=EA cos theta`
`rArr" "2xx10^(34)xx10^(-2)cos60^(@) rArr phi=802`
`rArr" "phi=40" weber"`