Question

Three lawn chairs, one made up of aluminum (heat capacity $ = 0.90J/K - g,$ one of iron (heat capacity $ = 0.45J/K - g,$ and, one of tin (heat capacity $ = 0.60J/K - g,$ are painted of the same color. On a sunny day which chair will be hotter to sit in?
A) iron chair
B) tin chair
C) aluminum chair
D) all, same

Answer 1

Hint: The amount of heat required to be supplied to a given mass of the material to produce a change in its temperature is called Heat Capacity. It depends on the temperature, pressure, and volume of the system.

Complete step by step solution:
Given data:
Heat capacity of aluminum $ = 0.90J/K - g$
Heat capacity of iron $ = 0.45J/K - g$
Heat capacity of tin $ = 0.60J/K - g$
Three chairs are painted the same color.
Hottest Chair =?
We know that metals are good thermal conductors. Due to this, the metals feel hotter or colder to the touch when compared to the other materials even though they are at the same temperature. Thus metals absorb the heat easily from the warmer objects and transfer the heat to colder bodies easily. Some metals will have the capacity of becoming hotter very fastly when compared with other materials.
A metal with a smaller heat capacity will rise to a higher temperature even though the same amount of the energy is added to the other material with a larger heat capacity.
Thus from the above-given data, it is clear that the iron chair is having a smaller heat capacity and thus it will rise to a higher temperature and becomes hot when compared with the other two metals. Hence the iron chair is the hottest chair to sit in.

Hence the correct option is A.

Note: When we touch a metal that is colder than our hand, our fingers lose heat and we feel cold and similarly, when we touch a metal that is hotter than our hand our fingers gain heat and we feel hot.