What would be the Iso-quant curve in the case of perfectly complementary factors ?

Question

Accepted Answer

The correct option is 1:

The Iso-quant curve represents all combinations of two factors of production (like capital and labor) that yield a constant level of output. In the case of perfectly complementary factors, the inputs must be used in a fixed proportion, meaning they cannot be substituted for one another at all. For example, a car requires exactly one steering wheel; using two steering wheels will not produce more than one car, nor can you reduce the number of steering wheels by increasing the number of engines. Because production can only increase when both factors increase simultaneously, the Iso-quant curve takes the shape of a right angle, or an L-shape. The fixed proportion means that increasing only one factor beyond the required ratio adds nothing to the total output, resulting in the vertical and horizontal segments of the curve where the Marginal Rate of Technical Substitution (MRTS) is zero or infinite.

The incorrect option is 2: Circular
A circular iso-quant is not standard in production theory and would imply highly unusual, non-economic substitution properties, often violating the principle that producers seek to minimize cost.

The incorrect option is 3: U-shaped
U-shaped curves are commonly seen in cost analysis (like Average Cost curves) but are not the characteristic shape for an Iso-quant. Iso-quants are typically convex to the origin, reflecting imperfect substitutability, not U-shapes.

The incorrect option is 4: Straight line falling from left to right
A straight line Iso-quant implies perfect substitutability between the two factors, meaning a factor can be completely replaced by the other while maintaining the same output level (constant MRTS). This is the exact opposite of perfectly complementary factors.