 And we will study the law of demand. Up till now we have studied many things related to the consumer behavior. And the general consumer behavior that we mostly see around our total market area or the general people that comes under the one domain by the repeated that becomes the law. So the law of demand because it entails the general behavior of the consumer that mostly consumers when they will be facing the decline in the price of the commodity for that commodity consumers will enhance its demand. Or otherwise whenever there will be increase in the commodity price consumer will tend to decrease its demand. So the general behavior over the market or general consumption patterns after repeatedly looking at the consumers the scientists who gave a complete law to our economist Charles that was 1690 or this relationship they said in the form of law of demand that there is always the inverse relationship between the price and the quantity demanded of the commodity. So this law of demand it tells that number one there will always be inverse relationship between quantity demanded and its own price. And higher the price quantity demanded will be low but the price and the quantity demanded they will be inversely to each other. And this law will be a qualitative statement but and this is not a quantitative statement that we are going to make this in the form of a equation. So according to this law we can see that price and the quantity they both will go in the opposite direction to each other. But this behavior when we see we count certain things on this that this will be include means the other things being the equal. It means that when we measure the effect of a change in the price on the quantity demanded we have to assume many things and those assumptions if not fulfilled this law will not be fulfilled properly. So what are those assumptions that we have to deal and what will be the behavior? When we come to the behavior we see that if we include a schedule it means we take units at price 10 the quantity demanded is 100 price increase quantity reduce again price increase quantity reduce. In this way when we plot the quantity demanded on X axis and the price of the commodity on the Y axis we draw a demand curve by joining the resultant points and it becomes in the form of a negative curve it means there is an inverse relationship between quantity demanded and the price and we must see that this demand curve that we have seen here this is the inverse demand curve because here we have seen not only one thing that due to the change in the price quantity demanded rather we have plotted quantity demanded on the X axis. So now coming to the assumptions we assume that the price of the related good it should be kept constant so here when we talk about related then related means that commodity for which we are making demand function or including we will consider only its change and apart from that all others which can be in demand function which will be different and in the same way it is facing in the consumption bundle it might be complements it might be its substitutes it might be other normal good we will keep the price constant and not only the price we will say that for that particular time of analysis the taste and preference of the consumer should be constant it means the demand of the consumer the quantity which is changing should be reflected from the price due to change in taste and the preference should not be reflected from that and we will take that effect in constant and the nominal income of the consumer should be kept constant and we will include the consumer in this form that its behavior is rational at every point and the income and wealth it is distributing equally if we talk about equally then we will say that if it is taking two commodities in its consumption bundle then it should not be of the corner solution means in which it is always buying only one commodity in fact mostly we assume that this laugh demand is mostly for normal goods and that limited substitutability is there and because all these factors which demand the consumer, its preference, its taste if we look at all these factors then an external factor is present in the market so the external factors of the market they are always affected through the various government policies the main fiscal policy can be taxed there can be some subsidy so keeping in view this assumption we have to consider that there will be no any type of the government policy which is affecting the demand of the consumer either positive or negative and at that time we will see that the market the market's size is not increasing sometimes the number of buyers or the number of sellers it can have the effect on the consumer's demand quantity that is why we assume all these factors that they are kept constant and then we will measure the change in the price and due to that change in the price what is the effect on the commodity demand now coming to the laugh demand we say that there is always an inverse relationship between price and quantity then what are the various factors and what are the various points because of which we assume that this inverse relationship is maintained if we see that there is always number one increase in sale means all the people present in the market they always want to buy more things if it is of less value and because they want to buy more then there is only one hurdle for them that is the price so this one point is used by the business and the market players will utilize the point of sale or the clearance sale to attract the people when we see the concept of diminishing marginal utility this always provides one explanation of this inverse relationship because one additional unit of the commodity it will have the less value for the consumer we can say that one additional successive unit of the commodity it yield less to the consumer and substitution and the income effect that we have already studied that there will be one income effect and there will be one substitution effect where the income effect can be positive and the negative but the substitution effect it will always be negative due to the change in the price considering these three factors we see that there is always certain situation that this laugh demand doesn't hold so what are the situations when our normal behavior of the laugh demand doesn't hold so we see that whenever there are the demand for the goods which are necessity and when there are certain given goods when the commodities that are just utilized on the form of the status or just to show off so this given good paradox or this weblant paradox they mostly they are the exception to the normal behavior and when the people sometime they are having a very strong expectation related to the future prices that if the price is going to decrease and we expect that now the consumer they will purchase more but rather people they are expecting that price will go down further and further so they will not respond accordingly and above all we have assumed mostly in our rational behavior that the consumer will be rational but this exception it will include that if the consumer is rational it is necessary for him to have ample or sufficient information related to commodity and the market but if the consumer is ignorant and he is not having the information then it cannot be expected from him to behave according to laugh demand and above all whenever there will be emergency condition related to the war situation the flood or something like this then this laugh demand will not be hold in its form