Question

if the electric field of a point charge were proportional to 1/r3 instead of 1/r2,would gauss law still be valid?Explain

Answer 1

Gauss law will not be valid for field which is not 1/r^2That is because area of the surface has the same dependence1/r^2 where r is typical size region.
When integrating the flux we have descent of fieldcompensated with increase of area.
If we have 1/r^3 field descent will be bigger and the Gausslaw will not hold.