1. The figure shows field lines due to three electric charges each of magnitude Q. The red circle indicates the intersection of a spherical Gaussian surface with the plane of the paper. The net electric flux out of the sphere is

2. The figure shows a pyramid with a square base. Each of the triangular side is an equilateral triangle. A charge Q is fixed at the centre of the base of the pyramid. The flux through any of the triangular sides is

3. The field in the cube of side L is given by , where a and b are constants. The total charge enclosed within the cube is

4. A point charge Q is situated at a distance d/2 directly above a square plate of side d. The electric field through the square is

5. A constant electric field passes through the hemispherical shell of radius R. The flux through the curved surface is