In: Physics
A rod is negatively charged by rubbing it with fur. It is brought near another rod of unknown composition and charge. There is a repulsive force on each.
(a) Is the first rod an insulator or a conductor? Explain.
(b) What can you tell about the charge of the second rod?
A rod is negatively charged by rubbing it with fur. It is brought near another rod of unknown composition and charge.
(a)
Electrons in a conductor are much more mobile than ions in any kind of solid. Therefore, if the rod is a conductor, electrons will quickly flow in such a way to minimize any potential difference between the fur and the rod. That is it will not be possible to achieve a measurable transfer of change by rubbing with a conductor the rod however gets negative charge. From which we can say that it is an insulator.
(b)
The charge of the second rod must also be negative because the force between the two rods is repulsive.