The law of supply is an economic principle that states that all things are equal and an increase in the price of a commodity will result in a corresponding increase in supply and vice versa.
What this simply means is that price and supply have a direct relationship. When there is an increase in the price of a good or service, producers or manufacturers will supply more of that good or service in order to make more profits from sales.
Also, when there is a drop in the prices of a good or service, there is bound to be a corresponding decrease in its supply because there is less profit to be made.
The law of supply is often used alongside the law of demand. So if demand increases, prices will increase and the producers will increase their supply accordingly.
The law of supply only holds true if all other factors are held constant. These factors include the cost of production, technological advances, taxes, availability of raw materials, etc.