In 18.3 and 18.7, 18.8 we have obtained the expression for the potential of the field of a point charge using numerical methods. When you have learned to difierentiate, prove that formula (18.25) leads to the expression for the field intensity of a point charge known from the Coulomb law.

In 18.3 and 18.7, 18.8 we have obtained the expression for the potenti

1.	In 18.3 and 18.7, 18.8 we have obtained the expression for the potential of the field of a point charge using numerical methods. When you have learned to difierentiate, prove that formula (18.25) leads to the expression for the field intensity of a point charge known from the Coulomb law.
Answer» Solution :In this case EQUIPOTENTIAL SURFACES are spheres with a common centre at the source, and radii normal to the surfaces. If the potential is `varphi=q..4pi epsi_(0)r,`the FIELD strength is `E=(dvarphi)/(dr)=-(d)/(dr)((q)/(4pi epsi_(0)r))=(q)/(4pi epsi_(0)r^(2))` and just this was to be proved.

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In 18.3 and 18.7, 18.8 we have obtained the expression for the potential of the field of a point charge using numerical methods. When you have learned to difierentiate, prove that formula (18.25) leads to the expression for the field intensity of a point charge known from the Coulomb law.

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