Consider a uniform electric field E=3×103^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?
Consider a uniform electric field E=3×103^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?
(a)
Electric field E=3×103i N/C, i.e., electric field is directed towards positive X-axis.
As the surface is in Y-Z plane, so the area vector (normal to the square) is along X-axis).
Area S=10×10=100cm2=10−2m2Area vector S=10−2m2^i
Using the formula of electric flux
ϕ=E.S=EScosθ =ES [∵angle between E and S is 0∘]ϕ=3×103×10−2=30N−m2/C
(b) Now, the area vector makes an angle of 60∘ with X-axis.
E=3×103^i N/CS=100cm2=10−2m2, θ=60∘
Using the formula of electric flux ϕ=E.Sϕ=EScosθ=3×103×10−2cos60∘=3×10×12=15N−m2/C
Note Remember that the direction of area vector is always perpendicular to the area of a face.
(a)
Electric field E=3×103i N/C, i.e., electric field is directed towards positive X-axis.
As the surface is in Y-Z plane, so the area vector (normal to the square) is along X-axis).
Area S=10×10=100cm2=10−2m2Area vector S=10−2m2^i
Using the formula of electric flux
ϕ=E.S=EScosθ =ES [∵angle between E and S is 0∘]ϕ=3×103×10−2=30N−m2/C
(b) Now, the area vector makes an angle of 60∘ with X-axis.
E=3×103^i N/CS=100cm2=10−2m2, θ=60∘
Using the formula of electric flux ϕ=E.Sϕ=EScosθ=3×103×10−2cos60∘=3×10×12=15N−m2/C
Note Remember that the direction of area vector is always perpendicular to the area of a face.
