Using the "conduction tester" on an object it was found that the bulb begins to glow.Is that object a conductor or an insulator? Explain.

A tester is used to check the conduction of electricity through two liquids ,labelled A and B. It is found that the bulb of the tester glows brightly for liquid A while it glows very dimly for liquid B. You would conclude that liquid A is a better conductor than liquid B. Liquid B is a better conductor than liquid A. both liquids are equally conducting. conducting properties of liquid cannot be compared in this manner.

Which of these can be used to obtain a real image having the same size as the object ?

Two charged conducting spheres of radii a and b are connected to each other by a wire. What is the ratio of electric fields at the surfaces of the two spheres? Use the result obtained to explain why charge density on the sharp and pointed ends of a conductor is higher than on its flatter portions.

Can any object have mechanical energy if its momentum is zero? Explain.