Consider the market for electricity. Suppose that a power plant dumps byproducts into a nearby river, creating a negative externality for those living downstream from the plant. Producing additional electricity imposes a constant per-unit external cost of $300. The following graph shows the demand (private value) curve and the supply (private cost) curve for electricity. Use the purple points (diamond symbol) to plot the social cost curve when the external cost is $300 per unit. 2000 1800 O Social Cost 1600 1400 O 0 Supply 1200 (Private Cost) 1000 PRICE (Dollars per unit of electricity) 600 400 O Demand 200 (Private Value) 2 6 QUANTITY (Units of electricity) The market equilibrium quantity is * units of electricity, but the socially optimal quantity of electricity production is _ units. To create an incentive for the firm to produce the socially optimal quantity of electricity, the government could impose a of $ per unit of electricity