1. The marginal external cost associated with air pollution increases with the annual output of a polluting industry. At the current competitive equilibrium level of output per year the marginal external cost is $10 per unit of output. To achieve efficiency,

a) a corrective tax of $10 per unit of output is required.
b) a corrective tax of more than $10 per unit of output is required.
c) a corrective tax of less that $10 per unit of output is required.
d) a corrective subsidy of $10 per unit of output is required.
e) a corrective subsidy of less than $10 per unit of output is required.

2. A positive externality results from the purchase of smoke detectors. If smoke detectors are sold in a competitive market,

a) the marginal social benefit of smoke detectors is less than the marginal private benefit received by any consumer.
b) the marginal social benefit will exceed the marginal private benefit received by any consumer.
c) in equilibrium the marginal social cost of smoke detectors will equal the marginal social benefit.
d) in equilibrium the marginal social benefit os smoke detectors is zero.

3. If a positive externality prevails in the market for smoke detectors, then when the market is in equilibrium,

a) the marginal social benefit of smoke detectors exceeds the marginal social cost.
b) the marginal social cost of smoke detectors exceeds the marginal social benefit.
c) the marginal social cost of smoke detectors is equal to the marginal social benefit.
d) more than the efficient amount of smoke detectors is sold.

4. Currently eight security guards patrol a condominium community each week. The number of guards has been determined by majority rule. Each voter pays a tax share of $50 per guard. If voter "M" is the median voter,

a) his marginal benefit from security guards is $50.
b) his marginal benefit exceeds that of any other voter.
c) the difference between his marginal benefit and $50 is at a maximum.
d) he would be made better off if more security guards were hired per week.