Air resistance is a special kind of frictional force that acts on objects as they travel through air. Identify the situation where this frictional force is ABSENT, from the ones given below:

A

Explanation:

The air resistance as frictional force will always exist whenever there is motion. And cease to exist whenever there is no motion.

Among all the options, a lamp fixed with a rod from the ceiling experiences no movement. Therefore, this frictional force is ABSENT in that situation.

force required to detach it is given by

charges are taken to be fundamental charge

now we have

so above is the minimum distance at which it will detach