(Geoff Riley et al. 2006) There are determinants in price elasticity of supply. One of the determinants is time period. In time period, it is divided into short run and long run. Short run is meant by a period of time short enough so that the quantity of one or more factors of production used to produce a specific good cannot be changed. The place capacity of individual producers and of the industry is assumed unchanged. Therefore, the short run is a stage of time that is too short to let the quantities of all the phenomena of the production to be changed. For example, the supply in apples is shown by Ss in Figure 2.1. The rise in demand is met through a bigger quantity changes (Q1 to Q2) and a smaller price changes (P1 to P2) than in the market period; price is as a result smaller than in the market period. The long run means that a period of time that all the necessary changes to phenomena of production is available. Therefore, all phenomena are variable in long run. For example, in apples industry, the individual farmer can use new equipment. Then, more farmers may be interested to apples production by rising up the demand and raise the price of apples. These changes mean an even bigger supply response; that means the supply curve SL is more elastic. The lower price that causes the price (P0 to P1) but the bigger result (Q0 to Q1) in response to the determined increase in demand. This is shown in Figure 2.2.

Figure 2.1 Figure 2.2

Next, another determinant is degree of substitutability. The producer will be interested to produce more of the goods when the price of the goods increases. The superior the degree of the substitutability factors of production process of one good and the production processes of other goods, the greater the elasticity of supply of that good. For example, field that is able to produce paddy can be use easily when the price of rice increases. The greater the substitutability of field and paddy will increase the quantity of paddy supplied in response to any given increases in price.