Price Elasticity
of Supply (ES)=\(\frac { \triangle Q }{ \triangle P } \times \frac { P }{ Q } =\frac { 5 }{ 5 } \times \frac { 10 }{ 5 } =2\)
ES=2 (supply is highly elastic as ES>1)
ES is always positive due to direct relationship between price and quantity supplied.

Price Elasticity of supply(ES) =\(\frac { \triangle Q }{ \triangle P } \times \frac { P }{ Q } \)
0.5=\(\frac { 15 }{ 15 } \times \frac { 5 }{ Q } \) ,i.e.,Q = 10
As price increases, then quantity supplied also increases. It means,
Final Output = Initial Output (Q) + Change in Quantity (\(\triangle Q\)) = 10 + 15 = 25 units

Price Elasticity of Supply (ES)=\(\frac { \triangle Q }{ \triangle P } \times \frac { P }{ Q } \)
\(1.25={{\triangle Q}\over{20}}\times{10\over4}\)
As price increases, then quantity supplied also increases. It means, New Quantity = Original Quantity (Q)+ Change in Quantity
(\(\triangle \)Q) = 4 + 10
= 14 units
New Quantity = 14 units.

(i) In the long period, supply is more elastic as all the factors can be changed and supply can be easily adjusted as per changes in price.
(ii) The supply curve during long period is elastic, i.e. percentage change in quantity supplied is greater than percentage change in price as shown below:

(i) In the short period, supply is relatively less elastic as firm can change the supply by changing the variable factors only, as fixed factors remain fixed during short period.
(ii) The supply curve during short period is inelastic, i.e., percentage change in quantity supplied is less than percentage change in price as shown below:

(i) The degree of responsiveness of quantity supplied to the changes in price of the commodity is known as price elasticity of supply.
(ii) Percentage Method: To measure price elasticity of supply, we use percentage method. According to this method, elasticity is measured as the ratio of percentage change in the quantity supplied to percentage change in the price. Price elasticity of supply (ES)
\(=\frac { Percentage\ change\ in\ quantity\ supplied }{ Percentage\ change\ in\ price } \)
Where,
Percentage change in quantity supplied
\(=\frac { change\ in\ quantity\ supplied(\triangle Q) }{ Initial\ Quantity\ Supplied(Q) } \)X100
Change in Quantity \((\triangle Q)\)
=New Quantity(Q₁)-Initial Quantity(Q) 
Percentage change in price
\(=\frac { change\ in\ Price(\triangle P) }{ Initial\ Price(P) } \times 100\)
Change in price \((\triangle P)\)=New price (P₁)-Initial Price (P)
Proportionate Method:
The percentage method can also be converted into the proportionate method. Putting the values of 1, 2, 3 and 4 in the formula of percentage method, we get, 
\(ES=\frac { \frac { \triangle Q }{ Q } \times 100 }{ \frac { \triangle P }{ P } \times 100 } =\frac { \frac { \triangle Q }{ Q } }{ \frac { \triangle P }{ P } } \)
Elasticity of Supply (Proportionate Method)=\(\frac { \triangle Q }{ \triangle P } \times \frac { P }{ Q } \)
Where, Q = Initial Quantity Supplied
\(\triangle \)Q = Change in Quantity Supplied
P = Initial Price
\(\triangle \)P = Change in Price

(i) When the number of firms in the industry increases, market supply also increases due to large number of producers producing that commodity.
(ii) So, due to increase in market supply, the supply curve shifts rightward as shown.

(i) This also influences the supply since price of inputs (rent, wages, interest, profit) constitutes the cost of production of a commodity.
(ii) An increase in the price of an input may lead to rise in cost of production, which will thereby decrease the production of a commodity shifting the supply curve to the left as shown.

(i) A unit tax is a tax that the government imposes per unit sale of output.
(ii) For example, suppose that the unit tax imposed by the government is Rs.3. Then, if the firm produces and sells 20 units of the goods, the total tax that the firm must pay to the government is
20 x 3 = 60.
(iii) So, if the unit tax increases, the firm's cost of production increases which will shift the supply curve leftward.

When there is technological progress in the firm, then cost of production will decrease, which leads to increase in the profit margin of the firm and thereby shifts the supply curve rightward as shown.

Note: As the three firms are identical, supply of the second firm (SS₂) and the third firm (SS₃) will be equal to the supply of first firm (SS₁).