var questions = new Array();
var choices = new Array();
var answers = new Array();
var response = new Array();

questions[0] = "1) In a power station, electricity is produced in the ...";
choices[0] = new Array();
choices[0][0] = "boiler";
choices[0][1] = "generator";
choices[0][2] = "turbine";

answers[0] = choices[0][1];

questions[1] = "2) ... is not a fossil fuel.";
choices[1] = new Array();
choices[1][0] = "Coal";
choices[1][1] = "Oil";
choices[1][2] = "Uranium";

answers[1] = choices[1][2];

questions[2] = "3) Nuclear fission takes place in ...";
choices[2] = new Array();
choices[2][0] = "solar cells";
choices[2][1] = "nuclear power stations";
choices[2][2] = "coal-fired power stations";

answers[2] = choices[2][1];

questions[3] = "4) An efficient power station ...";
choices[3] = new Array();
choices[3][0] = "changes much of the chemical energy in the fuel into heat energy";
choices[3][1] = "changes much of the chemical energy in the fuel into electricity";
choices[3][2] = "does not polute the atmosphere";

answers[3] = choices[3][1];

questions[4] = "5) The energy change in the generator of a power station is ...";
choices[4] = new Array();
choices[4][0] = "Kinetic into electricity";
choices[4][1] = "chemical into heat";
choices[4][2] = "heat into kinetic";

answers[4] = choices[4][0];

questions[5] = "6) Electricity can be produced directly from the Sun using ...";
choices[5] = new Array();
choices[5][0] = "solar cells";
choices[5][1] = "wind turbines";
choices[5][2] = "nuclear fission";

answers[5] = choices[5][0];

questions[6] = "7) The disadvantage of a nuclear power station is ...";
choices[6] = new Array();
choices[6][0] = "causes acid rain";
choices[6][1] = "long term storage of radioactive waste";
choices[6][2] = "causes global warming";

answers[6] = choices[6][1];

questions[7] = "8) Turbines in a hydroelectric power station turn by ...";
choices[7] = new Array();
choices[7][0] = "steam";
choices[7][1] = "falling water";
choices[7][2] = "wind";

answers[7] = choices[7][1];

questions[8] = "9) The main disadvantage of generating electricity by wind is ...";
choices[8] = new Array();
choices[8][0] = "noise";
choices[8][1] = "expensive to set up";
choices[8][2] = "not reliable";

answers[8] = choices[8][2];

questions[9] = "10) Burning of biomass does not cause global warming because ...";
choices[9] = new Array();
choices[9][0] = "biomass does not contain carbon";
choices[9][1] = "no carbon dioxide is released"; 
choices[9][2] = "the carbon dioxide released was only absorbed in the last year or so, not over millions of years";

answers[9] = choices[9][2];

questions[10] = "11) Kilowatt-hour is a unit of ...";
choices[10] = new Array();
choices[10][0] = "Electrical energy";
choices[10][1] = "Power";
choices[10][2] = "Time";

answers[10] = choices[10][0];

questions[11] = "12) A 1000 W electric kettle was used for 2 hours. The cost of using the kettle at 10p per kWh is ...";
choices[11] = new Array();
choices[11][0] = "2 pence";
choices[11][1] = "20 pence";
choices[11][2] = "200 pence";

answers[11] = choices[11][1];

questions[12] = "13) If electricity is transmitted without transformers in the National Grid, most of the energy will be ...";
choices[12] = new Array();
choices[12][0] = "the same, no loss";
choices[12][1] = "lost as heat from the cables";
choices[12][2] = "lost as sound from cables";

answers[12] = choices[12][1];

questions[13] = "14) These have a long life, require low maintenance, do not produce waste but their initial cost is high. ";
choices[13] = new Array();
choices[13][0] = "Nuclear power stations";
choices[13][1] = "Solar cells";
choices[13][2] = "Tidal power stations";

answers[13] = choices[13][1];

questions[14] = "15) Geothermal is ... because the heat from deep underground stays at a constant level.";
choices[14] = new Array();
choices[14][0] = "Cheap";
choices[14][1] = "Efficient";
choices[14][2] = "Reliable";

answers[14] = choices[14][2];



//response for getting 100%
response[0] = "Excellent, top marks!";
response[1] = "Revise power stations";
response[2] = "Revise power stations";
response[3] = "Revise power stations";
response[4] = "Revise efficiency";
response[5] = "Revise power stations";
response[6] = "Revise renewable energy resources";
response[7] = "Revise generating electricity: advantages and disatvantages";
response[8] = "Revise renewable energy resources";
response[9] = "Revise generating electricity: advantages and disatvantages";
response[10] = "Revise power stations";
response[11] = "Revise cost of electricity";
response[12] = "Revise cost of electricity";
response[13] = "Revise National Grid";
response[14] = "Revise generating electricity: advantages and disatvantages";
response[15] = "Revise renewable energy resources";
response[16] = "Revise generating electricity: advantages and disatvantages";