Question

Explain whether Gauss's law is useful in calculating the electric field due to three equal charges located at the corners of an equilateral triangle.

Answer 1

Gauss law is based on the principle that the solid angle subtended by any closed 3D figure at any point inside it is equal to 4π. Since the triangle is not a closed 3D surface, it does not subtend an angle of 4π at any point inside it. Thus, gauss law does not work here.