Question

Assertion- A brass tumbler feels much colder than a wooden tray on a chilly day.
Reason- The ability to conduct heat of brass is less than that of wood.
A. Both Assertion and Reason are correct and Reason is the correct explanation of Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion
C. Assertion is correct but Reason is incorrect
D. Assertion is incorrect but Reason is correct

Answer 1

Hint: Heat is a form of energy which can be transferred from one body to another. This is mainly due the difference in the temperature of the two bodies. Also heat always flows from a hot body to a cold body. It is measured in terms of joules.

Complete step-by-step answer:
We know that there are three types of heat transfer, namely conduction, convection, and radiation.
In conduction, the transfer of heat is due to the collision of the molecules of the medium. Observed generally in, solids, liquids, and gases.
In convention, the transfer of heat is due to the movement of the fluids in the system. Observed generally in fluids i.e. liquids and gases.
In radiation, heat is transferred in the form of electromagnetic radiation, through the medium.
Assume that you have two tumblers, one made of wood and another of brass, both containing water is kept in the open during a chilly day. When we touch any one of the tumblers, heat flows from our hands to the tumbler and we feel that the tumbler is cold. Clearly, we feel the tumbler is cold due to loss in heat from our hand. Now because brass is a better conductor of heat, i.e. it allows the flow of heat, while wood is an insulator and doesn’t allow the heat to flow through it. We feel that the brass tumbler feels much colder than a wooden tumbler.
Here, instead of wooden tumblers, we have a wooden tray.
Hence clearly the assertion is true but the reason is incorrect.
Thus the answer is C. Assertion is correct but Reason is incorrect.

So, the correct answer is “Option C”.

Note: That heat is transferred via three forms, namely conduction, convection, and radiation. These forms differ from each other due to the medium present. A body is said to be hot if the temperature of the body is greater than the temperature of the surrounding, similarly, a body is said to be cold if the temperature of the body is lower than the temperature of the surrounding.