Tag: introduction to electrostatics

Metals have loosely bound outer electrons that is they have charge carriers which can move easily (current) when a potential difference is applied. Therefore, these loosely bound outer electrons make metals good conductors. 

Iron and Silver are metals so they are conductors. While carbon is conductor in graphite and insulator in diamond form. So only option left is wood which an insulator.  

Silver is a better conductor, non magnetic but expensive material compared to copper therefore copper is generally used for electrical wiring.

Some materials have electrons that are tightly bound to the nucleus and are not free to travel within the substance. These materials are called insulators.
An electrical insulator is a material whose internal electric charges do not flow freely, and therefore make it very hard to conduct an electric current under the influence of an electric field.

When we touch a charged object, our body conducts its charges to the earth. That is why a charged body loses its charge, if we touch it with our hand. Human body is a very good conductor of electricity.

Answer is D.

Bakelite, or polyoxybenzylmethylenglycolanhydride, is an early plastic. It is a thermosetting phenol formaldehyde resin, formed from an elimination reaction of phenol with formaldehyde. It was developed by Belgian-born chemist Leo Baekeland in New York in 1907.
One of the first plastics made from synthetic components, Bakelite was used for its electrical nonconductivity and heat-resistant properties in electrical insulators, radio and telephone casings, and such diverse products as kitchenware, jewelry, pipe stems, firearms, and children's toys.
If the Bakelite is dry, it won't conduct electricity, however if it is wet and a high enough voltage is applied to it, it might conduct electricity.

Distilled water  is bad conductor of electricity.

Metals have electronic configuration such that there is always one, two or three electrons present which lie in the outer most shell and are loosely bounded. Therefore, in metals there are always more free electrons. 

The current does not flow through the insulators. We know that a large amount of current will flow through the conductor due to the presence of free electrons. Relatively small amount of current also flow through semiconductors or some alloys.