A point charge of is at the centre of a cubical Gaussian surface 55 cm on edge. We have to find through the surface.

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As the point charge of has been placed at the centre of a cube of edge 55 cm electric flux through each of its six faces will be equal. Instead of calculating the flux through a face of the cube from the electric field and the definition of flux, we will workout the answer of the problem from the Gauss’s law. We have

Therefore,