Consider an electric field E=E0x^, where E0 is a constant. The flux through the shaded area (as shown in the figure) due to this field is
(A)2E0a2
(B)2E0a2
(C)E0a2✓ Correct
(D)2E0a2
Answer: (C)
Solution
The electric flux through a surface is Φ=E⋅A, where A is the area vector (perpendicular to the surface). The shaded area appears to be a square of side a in a plane. The component of the electric field perpendicular to this surface determines the flux.
Since E=E0x^, the flux depends on the projected area perpendicular to the x-direction. For the geometry shown, the projected area is a2, giving:
Φ=E0⋅a2
JEE Advanced · 2011 · 10 Apr 2011 · Paper 1 · Single correct option