Q.What is an indifference curve? Explain any four properties of indifference curves.

An indifference curve joins combinations of two goods that give equal satisfaction; it has four standard properties.

An indifference curve is a curve joining all the different combinations of two commodities that give a consumer the same level of total satisfaction, so that the consumer has no preference between any two points on it — the consumer is indifferent.

Four key properties:

1. Downward sloping (negative slope). To keep satisfaction constant, giving up some of one good must be compensated by getting more of the other; both goods cannot decrease together without lowering satisfaction, so the curve cannot slope upward.
2. Convex to the origin. This reflects a diminishing marginal rate of substitution — as a consumer acquires more of one good, they are willing to sacrifice progressively smaller amounts of the other good for each further unit.
3. Higher indifference curves show greater satisfaction. A curve lying farther from the origin passes through points containing a larger quantity of at least one good with no less of the other, which any rational consumer prefers. …

Students often state the properties as unrelated facts to memorise; in an exam answer it is worth briefly explaining WHY each property holds (for example, convexity follows from d …