What is required to bring about a phase change 1.an increase or decrease in pressure 2.an increase or decrease in energy 3.an increase in energy only 3.a decrease in energy only

Answer

Correct answers are 1.an increase or decrease in pressure 2.an increase or decrease in energy

Explanation

All existing matter can undergo phase change it means they may transform from one state to another. phase change of a matter  may occur due to change in energy and change in pressures.

for example there is an ice cube which is a solid and if  we want to change it phase into liquid water for that purpose we have to supply some energy to ice cube it means we have to give some heat to ice cube. After supplying heat energy to the ice it will turn into water it means there is phase change from solid to liquid due to supplying the heat. Similarly we can change the liquid water into solid ice cube by taking heat energy(reducing temperature) from the liquid water  .

In some cases the matter doesn't want to undergo phase transformation. For example, oxygen will solidify at -361.8 degrees Fahrenheit at standard pressure.But , it can change to solid state at warmer temperatures when the pressure is increased.

the working equation for the angular size is the product of the physical size and 360 degrees divided by the product of two pi and distance from earth. the minimum size would be 0.559 degrees while the maximum size would be 0.49 degrees.