Question

State and explain three types of heat transfer.

Answer 1

There are 3 types of heat transfer as follows:
1. Conduction
2. Convection
3. Radiation

1.Conduction
In this type of heat transfer, physical contact is necessary between two substances. for example when water kept in a bowl is kept for boiling, the heat is transferred to water from bowl as there is physical contact.

2. Convection
Here there is no need for physical contact but there is requirement of a medium for heat transfer. For example a heater. The heat is transferred through the medium of air in the surrounding.

3. Radiation
Here there is no need for any physical contact or any medium. The heat can even transfer in vacuum. For example the sun rays heating up the earth or our surroundings which are a form of radiation.

Answer 2

Answer: there are 3 types of heat transfer:

1.conduction  

2.convection

3.radiation

Explanation:

1.conduction-when there is a direct contact between any two or more Items which are in different in temperature.For example,when we take some cold milk and try to boil it we keep it on the stove and there is a direct contact in between the vessel you took to pour the milk in and the fire and the heat is transferred from the fire to the cold milk and in some time the milk will come to the room temperature (if you off the stove in time).

2.convection-when the hot air rises top and the cold air comes down and that is because the hot air is less dense than the cold air.For example, let’s take the last one , so, when you take the milk of the stove after is gets more hotter than the room temperature you will be able to see some kind of smoke rising and that is the hot air which is going top.  

3.radiation-when you feel hot or cold without any direct contact.For example you are on a beach and sleep in the sand without any shade and after sometime you may notice that it is getting a little hot in there and that is because of the radiation which is given out by the sun.