Variation in supply

VARIATION IN SUPPLY
        If the quantity supplied changes due to change in the price, keeping all other factors constant, then it is called variation in supply.
A) Expansion or extension of supply :
B) Contraction of supply :
A) Expansion or Extension of supply :
     If supply rises due to rise in price, keeping all other factors constant, then it is called expansion of supply.
Diagram:

 In the above diagram, "SS" is the supply curve. Point 'a' shows that when price is "OP"  quantity supplied is "OQ" . when price rises from 'OP' to ' OP1' , quantity supplied rises from OQ to OQ1.
           This rise in the supply I.e. from OQ to OQ1  due to rise in the price I.e. from OP to OP1 shows the expansion of supply
 Here, the movement from point " a " to point " b " on the same supply curve depicts the expansion of supply.
B) contraction of supply:
      If quantity supplied falls due to the fall in price, keeping all other factors constant, then it is called " contraction of supply ".
Diagram:
     

    In the above diagram point " a " shows, when price is 'OP' quantity supplied is 'OQ'. Point ' b' shows, when price falls to OP1 quantity supplied also falls from OQ to OQ1. This movement from point a to point b (downward) shows the contract of supply.