Question

When two objects are in thermal contact the heat is transferred by:
A) Conduction
B) Convection
C) Radiation
D) None of these

Answer 1

Hint: The atoms of any object continuously vibrates against each other on its mean position. These transfers the heat present inside the object uniformly to every part of the body. There are only three ways of transferring heat conduction, convection and radiation. When bodies are in contact heat can transfer through conduction.

Complete answer:
The correct answer to this question is conduction. Conduction is the most significant means of heat transfer inside a solid or between solid objects in thermal contact. In conduction the heat is transferred through the vibration of atoms against each other. Whereas in convection the atoms also flow with the flow of heat and in radiation heat is transferred in the form of waves. When two objects are in contact the heat is transferred from one object to another through vibration of the first object’s atom.

For example: consider two metals, heat up one metal and bring in touch of second metal. Gradually the second metal also gets heat up due to contact with atoms of heated metal. The rate at which energy is conducted as the heat between two bodies depends on the temperature difference between the two bodies which are in contact with each other. The heat automatically flows from a hotter body to a colder body. The objects which conduct heat through them are called conductors, for example- metals. The objects which do not conduct heat through them are called insulators for example- rubber, plastic etc.

Note: When objects are in contact the heat is transferred due to the vibration of atoms and the matters don’t flow with the flow of heat. The main difference between conduction and convection is the flow of matter. So, they can be easily distinguished by understanding the flow of heat whether matter is flowing or not. And in radiation flow of heat occurs through waves.