Which one of the following is not an important energy conversion in a coal-fired power station?
A. chemical energy of coal → thermal energy of steam
B. thermal energy of steam → mechanical energy of turbine
C. mechanical energy of turbine → chemical energy of steam
D. mechanical energy of turbine → electrical energy from generator

Solution
Sources of energy other than fossil fuels are increasingly being used by power companies to generate electricity for domestic use.
Which one of the following energy sources is not available in Australia for domestic purposes?
A. wind power
B. nuclear fusion
C. solar energy
D. hydroelectricity

Solution

Natural gas can be burnt in a power station to provide electrical energy. Alternatively, natural gas can be fed into a fuel cell for electricity generation.
At the present time, which one of the following best compares the efÞ ciency and cost of generating electrical energy by these two methods in a city like Melbourne?

A. efficiency of fuel cell higher, cost per kJ of electricity from fuel cell lower
B. efficiency of fuel cell higher, cost per kJ of electricity from fuel cell higher
C. efficiency of fuel cell lower, cost per kJ of electricity from fuel cell lower
D.efficiency of fuel cell lower, cost per kJ of electricity from fuel cell higher

Solution