Question

Explain how a metal rim slightly smaller than a wooden wheel can be fixed on it.

Answer 1

Hint: The metals undergo the process of expansion when heated, because the constituent molecules absorb the energy which is being given to them, and the distance between the molecules increases a bit, resulting in the expansion.

Complete step by step answer:
An iron rim is made in order to make the wooden wheel work for a longer period of time. So, in order to give it a tight fix the rim is usually made smaller than that of the size of the wheel. We know that when metals undergo the process of heating, it expands, meaning the volume of the metal increases. This is because generally the molecules from which the iron is made are tightly packed in nature but when we heat that piece of metal under consideration, we are providing heat to the system and the molecules of the metal absorb that heat and the bond between them loosens up a bit. This results in an increase in the distance between the molecules, as compared to the distance between the molecules before heating. As a result, the total volume of the metal expands. If we consider the question, the rim is made up of iron, which is a metal.
So, when it is heated it clogs easily into the wheel and then when it cools it fixes itself very tightly over the wheel giving it life.
This is the reason why metal rim is always made slightly smaller than the wooden wheel, the metal rim is heated, upon heating the ring expands and fits into the wheel.

So, the correct answer is Option A.

Note: The metal rim is always made slightly smaller than the wooden wheel. The metal rim is heated at first and on heating the rim expands and accordingly fits onto the wheel. Coldwater is then put over the rim because of cooling of the metal rim contracts and fits tightly onto the wooden wheel