Question

Which of the following is not a good conductor of heat?
(a) Steel Plate
(b) Water
(c) Iron rod
(d) Copper wire

Answer 1

Hint: Objects made of metals can quickly conduct unwanted heat right up to our hands and objects must have free electrons to conduct heat or electricity through them.

Complete step by step answer:
Materials that can easily conduct heat through them are good conductors of heat.
Materials that do not allow heat to flow through them are bad conductors of heat.
Material should have free electrons for conduction. Copper, Steel and Iron are metals and have free delocalized electrons which are useful for conduction of heat and electricity. The electrons are free to move throughout the metal structure and will help in conduction.
Whereas water is a non-metal and it does not have free electrons in it. Water is a solution and has electrically neutral molecules. There are no ions present in the water to carry electric charges. Water can also be used as an insulator.
So, the answer is Option B, Water.

Additional Information: Conductors are the substances which allow electricity (electric currents) to slide through them. Conductors also transmit the heat or light from one source to another source. Copper, Silver, Gold, Aluminum, aqueous solutions of salts are some of the examples of good conductors.

Note:The number of valence electrons in an atom is what makes a material able to conduct electricity. Good conductors have one valence electron, semiconductor has 4 valence electrons and bad conductors (insulators) have 8 valence electrons. Finding the valence electrons is an easy way to know the conductivity of a material.