The neoclassical approach to the demand for factors of production examines how firms respond to changes in the quantity of labor employed. We analyze the relationship between the quantity of labor employed and resulting output level. The short-run production function entails how a firm's output changes with varying levels of labor employed while keeping capital constant. As labor increases, output grows, but with diminishing returns. The concept of the marginal physical product of labor (MPPL) captures this relationship, representing the additional output resulting from employing one more unit of labor. Intuitively, as more labor is used alongside fixed capital, diminishing marginal productivity becomes inevitable