Answer the following questions in about 150 words each: (a) Examine the role of price elasticity of demand in determining the…

(a) Price Elasticity and Price Discrimination

In third-degree price discrimination, a monopolist segments the aggregate market into distinct sub-markets to maximize total profit. The equilibrium condition across markets requires equating marginal revenue in each market to the common marginal cost (MR₁ = MR₂ = MC).

Using the relationship MR = P(1 - 1/|e|), the pricing rule becomes: P₁(1 - 1/(|e₁|)) = P₂(1 - 1/(|e₂|)) = MC

This formulation reveals that the price charged is inversely related to the price elasticity of demand (|e|). In the sub-market with relatively inelastic demand (|e₁| < |e₂|), consumers are less responsive to price hikes, allowing the monopolist to charge a higher price (P₁ > P₂) to extract a larger share of consumer surplus. Conversely, in the elastic sub-market, a lower price is set to stimulate sales volume.

Thus, demand elasticity does not merely modulate prices; it serves as the necessary criterion for discriminatory pricing. If elasticities across sub-markets are identical, price discrimination yields no additional profit over uniform monopoly pricing.

(b) Backward Bending Labour Supply Curve

The supply of labour reflects an individual's constrained utility maximization between income (representing market goods) and leisure. A change in the wage rate (w) produces two simultaneous opposing forces:

The Substitution Effect (SE) raises the opportunity cost of leisure as wages rise, inducing the worker to substitute leisure with work, thereby increasing hours worked (an upward-sloping supply).

The Income Effect (IE) operates because higher wages increase real income for the same hours worked. Assuming leisure is a normal good, higher income induces greater demand for leisure, incentivizing fewer hours of work.

At lower wage levels, the substitution effect dominates (|SE| > |IE|), making the labour supply curve positively sloped. However, beyond a threshold wage (w^*), the income effect becomes dominant (|IE| > |SE|). At this point, the worker prioritizes leisure over marginal income gains, causing the labour supply curve to bend backward.

(c) Major Differences Between Classical and Keynesian Macroeconomics

Classical and Keynesian macroeconomics diverge fundamentally on market clearing, the role of aggregate demand, and policy intervention:

Say's Law versus Effective Demand: Classical economics adheres to Say’s Law ("supply creates its own demand"), assuming all income is spent. Keynes rejected this, arguing that output and employment are determined by the level of effective aggregate demand (AD = C + I + G + NX).

Wage-Price Flexibility versus Rigidity: Classicals assumed complete, instantaneous price and nominal wage flexibility, ensuring that labour markets automatically clear. Keynes posited nominal wage rigidity downwards due to institutional factors, contracts, and money illusion.

Equilibrium State: Classical models postulate that the economy automatically self-corrects to a full-employment equilibrium (Y = Y_f). Keynes demonstrated that economies can settle at a stable underemployment equilibrium with persistent involuntary unemployment.

Policy Stance: Classical economists advocated laissez-faire, viewing money as neutral (Classical Dichotomy). Keynes advocated discretionary state intervention, particularly counter-cyclical fiscal policy, to manage aggregate demand.

(d) Internal Rate of Return (IRR) in Investment Theory

The Internal Rate of Return (IRR) is the endogenous discount rate (r) that equates the present value of expected future net cash flows from an investment project to its initial capital outlay (C₀). Formally, it is the rate at which Net Present Value (NPV) equals zero: Σₜ₌₁ⁿ (Rₜ)/((1 + r)^t) - C₀ = 0

Importance and Decision Rule: IRR represents the marginal efficiency of capital (MEC). The investment criterion dictates that a project is accepted if its IRR > k (where k is the market cost of capital or hurdle rate), and rejected if IRR < k. In aggregate investment theory, projects are ranked by IRR to construct the investment demand schedule.

Limitations: IRR assumes cash flows are reinvested at the project's internal rate rather than the cost of capital. Furthermore, non-conventional cash flows (alternating signs) produce multiple IRRs, and for mutually exclusive projects of different scales, IRR can conflict with NPV rankings.

(e) Open Market Operations: Availability versus Cost of Credit Dilemma

Open Market Operations (OMOs) involve the purchase or sale of government securities by the central bank to influence monetary aggregates. Affecting both the availability (quantity of credit) and the cost of credit (interest rate) simultaneously is difficult due to the interdependence of price and quantity in money markets.

When the central bank purchases securities, it injects reserve money into commercial banks, augmenting credit availability via the money multiplier. Simultaneously, bond purchases drive up bond prices, lowering yields and reducing the cost of credit.

However, the central bank cannot simultaneously fix both an exogenous reserve quantity target and an interest rate target. If it targets a specific credit volume, the market-clearing interest rate must adjust freely, inducing volatility in borrowing costs. Conversely, if it targets an interest rate (cost channel), it must supply or absorb whatever quantity of reserves the market demands at that rate, surrendering control over credit availability.

This conflict is exacerbated in a liquidity trap or at the zero lower bound, where expanding reserves via OMOs fails to reduce borrowing costs further due to an infinitely elastic demand for money.