A Demand Analysis — Economics STD 12 Commerce / Arts — Question

(A) Introduction : The law of demand is one of the important law of consumption which explain the functional relationship between price and quantity demanded of a commodity. Prof. Alfred Marshall in his book ‘Principle of Economics’ which was published in 1890, has explained the consumer’s behaviour as follows:(B) Statement of the Law : According to Prof. Alfred Marshall, “Other things being equal, higher the price of a commodity, smaller is the quantity demanded and lower the price of a commodity, larger is the quantity demanded.
In other words, other things remaining constant, demand varies inversely with price. Marshall’s law of demand describes the functional relationship between demand and price. It can be presented as:
Dx = f(Px)
where D = Demand for Commodity
x = Commodity
f = function
Px = Price of a commodity
(C) Assumption :

• Prices of Substitute goods remain constant : The price of substitute goods should remain unchanged, as change in the price will affect the demand for the commodity.
• Prices of Complementary goods s remains constant : A change in the price j of one good will affect the demand for other,  thus the prices of complementary goods  should remain unchanged.
• No Expectation about future changes jj in prices: The consumers do not expect any \ significance rise or fall in the future prices.
• No change in Taxation Policy : The level of direct and indirect tax imposed by the government on the income and goods should remain constant.
• Constant Level of Income : Consumer’s income must remain unchanged because if income increases, consumer may buy more even at a higher price not following the law of demand.
• No Change in Tastes, Habits, Preference, Fashions, etc. : If the taste changes then the consumers preference will also change which will affect the demand. When commodities are out of fashion, then demand will be low even at a lower price.

(D) Explanation of the law of Demand :
The law of demand is explained with the help of the following demand schedule and diagram:
Demand SchedulePrice of Commodity ‘X’ (in Rs.)Quantity Demanded of Commodity ‘X’ (in kgs)501402303204105From the above demand schedule we observe that at higher price of ₹ 50 per kg, quantity demanded is 1 kg. When price fall from ₹ 50 to ₹ 40, quantity demanded rises from 1 kg to 2 kg. Similarly, at price ₹ 30 quantity demanded is 3kg and when price falls from ₹ 20 to ₹ 10 quantity demanded rises from 4 kg to 5 kg. This shows an inverse relationship between price and demand.https://pg-data.sgp1.digitaloceanspaces.com/chapter_wise/16402/Q10.png" alt="Image" width="262" height="" />In the above diagram X-axis represent quantity demanded and Y-axis represent the price of the commodity. The demand curve DD slopes downwards from left to right ] showing an inverse relationship between price and demand. It has a negative slope.(E) Exceptions to the Law of Demand :
No, I do not agree with this statement.
There are some important cases in which the demand for the commodity is greater when price rises and smaller when price falls. Such cases are called exceptions to the law of Demand. In such case, demand curve slopes upwards from left to right and it has a positive slope.

• Prestige Goods : Rich people buy more expensive goods like gold, diamonds, etc., even when there prices are high to maintain their status.
• Giffen Paradox : Demand for low quality goods and inferior goods decrease even if there prices falls.
  According to Sir Robert Giffen when price of bread declined, people did not buy more because of increase in their real income and they prefer to buy superior goods like meat.
• Speculation : People are tend to buy more commodities if they expect prices to rise further. E.g. prices of oil, sugar, etc., are expected to rise before Diwali, so people buy more of these commodities even at higher price.
• Habitual goods : Due to habit of
  consumption, certain goods like tea is purchased in required quantities even at higher price.
•  Ignorance : Sometimes people completely ignore the price of commodity and buy more of that commodity ignoring higher price.
• Price Illusion: Consumer feels that good at higher price are of better quality, therefore demand for such goods are higher even at rise in their prices.
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