One ton of coal is burned by a power plant every minute. The energy produced when one kg of coal is burned is 3.2 x 10^7 joules. The electric power produced is 2 MW. Calculate:
a) energy produced by the burning of coal per minute.
b) electric energy produced per minute (in joules).
c) energy dumped into the environment per minute (J).
d) the efficiency of the power plant.