In microeconomic theory, a firm operates with a mix of fixed and variable costs in the short run. However, when transitioning to the long-run production period:
all costs become variable.
variable costs become sunk costs.
all costs become fixed.
fixed costs consistently exceed variable costs.
156 exam-style questions on AQA A Level Economics 1.4 Production, costs and revenue, covering 1.4.1 Production and productivity, 1.4.2 Specialisation, division of labour and exchange, 1.4.3 The law of diminishing returns and returns to scale (A-level only), 1.4.4 Costs of production, 1.4.5 Economies and diseconomies of scale, 1.4.6 Marginal, average and total revenue, 1.4.7 Profit, and 1.4.8 Technological change (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.