A bird perches on a bare high power line but nothing happens to it, while a man standing on the ground suffers a shock on touching the same line. Why?

What is the equipotential surface for a single positive charge at the origin?

What is the equipotential surface for a uniform electric field parallel to z-axis.

There are two conducting spheres of radii $r_1 \& r_2$. Find the ratio of charges on them if both of them are at the same potential.