Question

1A) What happens when two objects in thermal equilibrium are brought into contact?

1B) What happens when two objects not in thermal equilibrium are brought into contact?

give examples along with answers

Answer 1

1(A)-When two bodies are in thermal equilibrium then their temperatures will be same. As we know that heat can only flow from a body at Higher temperature to a body at lower temperature.Since both bodies have same temperature so when they kept into contact then there will be no flow of heat it between them.

For eg-Let a cup of tea and a coin are kept into a room for a long time then both will acquire the temperature of room i.e. they are in thermal equilibrium.Now if we drop the coin into the tea then there is no rise or fall in the temperature of coin because there is no exchange of heat between them.

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1(b) if two objects are not in thermal equilibrium then their temperature will be different so when they kept into contact then heat flows from the body at Higher temperature to the body at lower temperature until the temperature of both become same.

For eg-If we heat a coin 'A' to some high temperature and put it on another coin 'B' which is at room temperature.Now we measure the temperature of both coins then we see that temperature of coin A decreases while temperature for coin B increases.After some time temperature of both coin become same.Now both coins are in thermal equilibrium and now their is no exchange of heat between them...