3 Further formatting fixes. Please be more thorough when editing posts for formatting - this should only happen once. edited May 18 '15 at 18:01 Emilio Pisanty 90.4k2323 gold badges228228 silver badges466466 bronze badges If we assume potential at infinity to be zero and earthEarth to be spherical then the potential at the surface of the earth is given by $$\frac{kq}{r}$$,$${kq}/{r}$$,where where $$k$$ is a constant  ,  $$q$$ is the charge on earth and $$r$$ its radius.As As $$q$$ is extremely small and $$r$$ very large, so the potential at earth'sEarth's surface is almost zero.So So for all practical purposes we assume its potential to be zero.The The potential at infinity is assumed to be absolutely zero whereas that on earth'sEarth's surface almost zero. If we assume potential at infinity to be zero and earth to be spherical then the potential at the surface of the earth is given by $$\frac{kq}{r}$$,,where $$k$$ is a constant  ,$$q$$ is the charge on earth and $$r$$ its radius.As $$q$$ is extremely small and $$r$$ very large, so the potential at earth's surface is almost zero.So for all practical purposes we assume its potential to be zero.The potential at infinity is assumed to be absolutely zero whereas that on earth's surface almost zero. If we assume potential at infinity to be zero and Earth to be spherical then the potential at the surface of the earth is given by $${kq}/{r}$$, where $$k$$ is a constant,  $$q$$ is the charge on earth and $$r$$ its radius. As $$q$$ is extremely small and $$r$$ very large, the potential at Earth's surface is almost zero. So for all practical purposes we assume its potential to be zero. The potential at infinity is assumed to be absolutely zero whereas that on Earth's surface almost zero. 2 improved formatting; edit approved May 18 '15 at 17:54 AV23 2,81066 silver badges1717 bronze badges If we assume potential at infinity to be zero and earth to be spherical then the potential at the surface of the earth is given by kq/r$$\frac{kq}{r}$$,,where k$$k$$ is a constant ,q$$q$$ is the charge on earth and r$$r$$ its radius.As q$$q$$ is extremely small and r$$r$$ very large, so the potential at earth's surface is almost zero.So for all practical purposes we assume its potential to be zero.The potential at infinity is assumed to be absolutely zero whereas that on earth's surface almost zero. Sanjay Bisht If we assume potential at infinity to be zero and earth to be spherical then the potential at the surface of the earth is given by kq/r,,where k is a constant ,q is the charge on earth and r its radius.As q is extremely small and r very large, so the potential at earth's surface is almost zero.So for all practical purposes we assume its potential to be zero.The potential at infinity is assumed to be absolutely zero whereas that on earth's surface almost zero. Sanjay Bisht If we assume potential at infinity to be zero and earth to be spherical then the potential at the surface of the earth is given by $$\frac{kq}{r}$$,,where $$k$$ is a constant ,$$q$$ is the charge on earth and $$r$$ its radius.As $$q$$ is extremely small and $$r$$ very large, so the potential at earth's surface is almost zero.So for all practical purposes we assume its potential to be zero.The potential at infinity is assumed to be absolutely zero whereas that on earth's surface almost zero. 1 answered May 18 '15 at 17:18 Sanjay Bisht 3111 bronze badge If we assume potential at infinity to be zero and earth to be spherical then the potential at the surface of the earth is given by kq/r,,where k is a constant ,q is the charge on earth and r its radius.As q is extremely small and r very large, so the potential at earth's surface is almost zero.So for all practical purposes we assume its potential to be zero.The potential at infinity is assumed to be absolutely zero whereas that on earth's surface almost zero. Sanjay Bisht