Revision: Understanding Economics Economics ISC (Commerce) Class 11 CISCE

1. “Utility is the ability of a good to satisfy a want.” (Prof. Hibdon)
2. “Utility may be the quality which makes a thing desirable.” (J.S. Nicholson)

• "The marginal utility which results from a unit increase in consumption." -Prof. Boulding
• "Marginal utility is an addition made to total utility by consuming one more unit of a commodity." -Prof. Chapman

Marginal utility refers to the additional utility derived from the consumption of an additional unit of a commodity.

Total utility refers to the total satisfaction derived by the consumer from the consumption of a specific quantity of a commodity.

According to Prof. Leftwitch, "Total utility refers to the entire amount of satisfaction obtained from consuming various quantities of a commodity."

1. According to Chapman: "The more we have of a thing, the less we want additional increments of it or the more we want not to have additional increments of it."
2. According to Anatol Murad, "The law states that other things being equal, the marginal utility of a stock decreases as the quantity of the stock increases."
3. According to Samuelson, "As the amount consumed of a good increases, the marginal utility of the good leads to a decrease."

"Money is anything which has the legal power to act as a medium of exchange and to discharge debt."
Under this definition, only items backed by government authority — currency notes and coins — qualify as money. In the words of Robertson: "Money is anything which is widely accepted in payment for goods or in discharge of other kinds of business obligations."

Gowther defines money as, "Money is anything that is generally acceptable as a means of exchange and at the same time, acts as a measure and as a store of value".

The term ‘market’ refers to the whole region in which buyers and sellers are in close contact to effect the purchase and sale of a product.

In economics, the term market refers to the mechanism or arrangement by which buyers and sellers of a commodity are able to interact with each other for having economic exchange and are able to strike a deal about the price and the quantity to be bought and sold.

“A market is the set of all actual and potential buyers of a product.”, Phillip Kotler

“Market includes both place and region in which buyers and sellers are in free competition with one another.”, Pyle

“A market means a body of persons who are in intimate business relations and carry on extensive transactions in any commodity.”, Jevons

“A market is a centre in which forces leading to exchanges of title to a particular product operate and towards which and from which the actual goods tend to travel.”, Clark and Clark

An oligopoly is a market structure in which a small number of large firms dominate the industry. These firms sell similar or differentiated products, and each firm’s decisions (such as pricing or output) directly affect the others, making them interdependent.

According to Augustin Cournot, “Economists understand the term 'market', not any particular marketplace in which things are bought and sold, but the whole of any region in which buyers and sellers are in such close contact with one another that the prices of the same goods tend to equality easily and quickly.”

• "Investment refers to the increment of capital equipment." — J.M. Keynes
• "By investment we do not mean the purchase of existing paper securities, bonds, debentures or equities, but the purchase of new factories, machines and the like". — Stonier and Hague
• "Investment expenditure includes expenditure for producer’s durable equipment, new construction and the change in inventories." — Peterson

Aggregate demand: Aggregate demand implies the total demand of final goods and services by various individuals in all the sectors in an economy. It expresses the total demand in terms of money. In this manner, it can be defined as the actual aggregate expenditure incurred by all the people in an economy on different goods and services.

AD = C + I + G + (X – M)
Where,
Demand by households - Private consumption expenditure (C)
Demand by firms - Private investment expenditure (I)
Demand by government - Government expenditure (G)
Demand by foreign sector- Net exports (X – M)
Where, X is exports and M is imports.

Aggregate supply refers to the aggregate production planned by all the producers during an accounting year. In other words, aggregate supply indicates the total amount of goods and services produced within an economy at a given general (or overall) price level during an accounting period. The aggregate supply function is represented as follows.

`"AS" = f (barN, barL, barK, barT)`

where,

AS = Aggregate supply

N = Natural resources

L = Labour

K = Stock of capital

T = State of technology

The Aggregate Supply Function (ASF) is a schedule that presents the different amounts of income that all entrepreneurs in an economy need to obtain from selling output at different levels of employment.

Total Utility:
\[TU_n=MU_1+MU_2+...+MU_n\]

When more than one unit is added:
\[MU=\frac{\Delta TU}{\Delta Q}\]

Marginal Utility:
\[MU_n=TU_n-TU_{n-1}\]

P_I = `I / Y`
PI = Propensity to invest, I = Aggregate Investment, Y = Aggregate Income

The relationship between investment and the rate of interest can be written as:

I = f(r)

Here:

• I = Investment, the planned amount of investment; it is the dependent variable.​
• r = Rate of interest; it is the independent variable that influences investment.​

This notation means that the level of investment depends on the rate of interest.

• Historical Significance: Ragnar Frisch's 1933 contribution established systematic economic analysis frameworks.
• Scale Distinction: Microeconomics studies individual units; macroeconomics examines aggregate systems.
• Greek Origins: 'Mikros' (small) and 'Makros' (large) provide intuitive understanding of scope.
• Interconnected Analysis: Both perspectives are necessary for comprehensive economic understanding.
• Real-World Relevance: Economic decisions at all levels affect daily life and national prosperity. 

Macroeconomics = Understanding the big picture of how India's economy affects your daily life, from job opportunities to price changes to government policies.

• Microeconomics zooms in on individuals & firms; macroeconomics zooms out to see the big economy.
• Micro answers: “How is this product priced?” Macro answers: “Is the economy growing?”
• Both are essential to understanding how economies function.

• Utility means want-satisfying power.
• It is subjective, varies with time/place, and forms the base of demand.
• Utility differs from usefulness, pleasure, and satisfaction—each has a unique meaning in economics.
• Common types include form, place, time, service, knowledge, and possession utility. 

• Total utility = total happiness from all units.
• Marginal utility = extra happiness from one more unit.
• Marginal utility usually decreases as we consume more.
• When marginal utility becomes zero, total utility is at its maximum.
• If you keep consuming, marginal utility can turn negative (“too much of a good thing!”).

• Given by French engineer Gossen
• Also called Gossen’s First Law
• First given by H.H. Gossen, systematically explained by Alfred Marshall
• As consumption increases, marginal utility decreases
• Other things remaining constant
• Each extra unit gives less satisfaction.
• Utility may become zero or even negative if overconsumed.
• Law helps explain real consumer and economic behaviour.

• Inflation = persistent + appreciable + general rise in prices — all three must be present.​
• A 2–3% annual inflation is healthy; it becomes a problem only when excessive.
• Demand-Pull Inflation = too much demand; too little supply → prices rise.
• Cost-Push Inflation = rising costs (wages/oil/monopoly power) → producers raise prices.
• Three sub-types of cost-push: wage-push, profit-push, and supply shock (oil shock).
• The inflation rate measures the % increase in average prices year over year.

• Money eliminates barter system problems by providing a common medium of exchange.
• Three main functions: medium of exchange, measure of value, store of value.
• Must be generally acceptable to function as money.
• Modern economy completely depends on money for smooth transactions.
• Digital payments are the newest evolution in money's history. 

• In common language, a market is a place where buying and selling occur.
• In economics, a market is any arrangement that allows buyers and sellers to meet (physically or virtually), decide a price, and exchange a commodity or service.​
• A market can be local, national, or international.
• Essential elements of a market: commodity, buyers and sellers, area of operation, communication/contact, and price.​
• There are two main ways to define a market: geographical (place‑based) and functional (activity‑based).​
• Competition among buyers and sellers tends to produce one prevailing price for the same commodity at the same time within a market.​

• Economic investment = addition to physical capital + change in inventories — NOT buying shares/bonds​
• Autonomous investment is income-inelastic, welfare-driven, mostly by government; drawn as a horizontal line​
• Induced investment is income-elastic, profit-driven, mostly private; drawn as an upward-sloping line​
• Gross Investment = Net Investment + Depreciation; net investment positive means capital accumulation
• Ex-ante = planned; Ex-post = actual; equilibrium requires ex-ante S = ex-ante I​
• Investment function I = f(r) is downward-sloping — higher interest means less investment​
• Invest when MEI > Rate of Interest; stop when MEI = Rate of Interest​