Question

please answer the 9th one with diagram

Answer 1

Demand refers to the amount of some good or service consumers are willing and able to purchase at each price. Demand is based on needs and wants—a consumer may be able to differentiate between a need and a want, but from an economist’s perspective they are the same thing. Demand is also based on ability to pay. If you cannot pay, you have no effective demand.

The law of demand states that when the price of a commodity falls then the quantity demanded rises and vice versa.
Demand curve is downward sloping.

Supply refers to the amount of some good or service a producer is willing to supply at each price. Price is what the producer receives for selling one unit of a good or service. A rise in price almost always leads to an increase in the quantity supplied of that good or service, while a fall in price will decrease the quantity supplied.

The law of supply states that when the price of a commodity rises then its supply rises too and vice versa.
Supply curve is upward sloping.

The point at which demand and supply of the commodity are equal that point is called market equilibrium.
 Here, Demand And Supply Curve INTERSECT each other.

The price corresponding to equilibrium point is called  EQUILIBRIUM PRICE.

This is shown in the figure.....

P is equilibrium price
E is equilibrium point where demand = supply.
In figure, DD is demand curve And SS is supply curve of commodity.
At point E demand is equal to supply and hence it is point of equilibrium.
OP is Equilibrium Price.