# A flat surface of area 2.60 m^2 is rotated in a uniform electric field of magnitude E = 6.35 * 10^5 N/C.

A flat surface of area 2.60 m2 is rotated in a uniform electric field of magnitude E = 6.35  105 N/C.

(a) Determine the electric flux through this area when the electric field is perpendicular to the surface.
N · m2/C

(b) Determine the electric flux through this area when the electric field is parallel to the surface.
N · m2/C
asked Feb 10, 2012 in Physics

The formula for electric flux is as follows:

Electric flux = E*A (* E = electric field, A = area)

and if electric flux is at an angle from the normal (which is perpendicular) the formula is:

Electric flux = E*A*cos(theta)   (* E = electric field, A = area, theta = angle between the normal of E and A)

So for part A, the field is perpendicular so we use the first formula.

Electric flux = E*A

E =  6.35  105 N/C

A = 2.60 m2

Now plug in the values into the formula.

Electric flux = 6.35  105 N/C  *   2.60 m   =    1651000 N · m2/C

Electric flux = 1651000 N · m2/C

Part B, the electric field is parallel, so it is at an angle of 90 from the normal.

So use the second formula:

Electric flux = E*A*cos(theta)

cos(90) = 0,

so therefore the electric flux will be 0.

Electric flux = 0

answered Feb 14, 2012 by ~Expert~ (3,020 points)
selected Feb 15, 2012 by awesome