Market equilibria when supply is changed

Q. What will happen on market equilibria when supply is changed (increased or decreased)? 

Ans.   

(a) Increase of Supply and Market Equilibrium: When supply is increased the supply curve will shift to the right because for every level of price supply increases. 

This will cause (i) equilibrium price to fall and (ii) equilibrium quantity to increase given the downward sloping demand curve. However the situations will be different when the demand curves are exceptional (perfectly elastic or inelastic or positively sloped).

(b) Decrease of Supply and Market Equilibrium: When supply is decreased the supply curve will shift to the left because for every level of price supply decreases. 

This will cause (i) equilibrium price to increase and (ii) equilibrium quantity to decrease given the downward sloping demand curve. However the situations will be different when the demand curves are exceptional (perfectly elastic or inelastic or positively sloped).