Thanks all of you for your suggestions. From the discussion what I
have understood is that the potential of any point to the earth
depends upon the charge of the point, distance of the point from the
ground (ground capacitance!!).
Thus to evaluate the potential difference (p.d.) between the floating
star point and the ground we must be able to evaluate the charge of
the star point. DK described that the p.d. depends on the ground
capacitance, overhead cloud. This is because it affects the charge of
the star point, am I right DK? But I still don=92t know how to evaluate
the charge?
When the star point is connected to the earth, we are simply putting a
conductor between two plates of the capacitor i.e. earth and the star
point which makes the p.d between them zero and all the charge at star
point will be drained to the earth.
Pls give ur suggestions.
