The foundational principle in computing history that predicts the number of transistors on a microchip will approximately double every two years, resulting in a consistent increase in processing efficiency and a decrease in relative cost, is known as:

💡 Explanation:

Moore's Law, coined by Intel co-founder Gordon Moore, describes the long-term trend where the density of integrated circuits (and thus processing power) doubles approximately every two years. This principle has been the primary driver of rapid technological advancement and miniaturization in the computer industry.