Energy and the Environment

Balancing global energy demand against a viable biosphere, and the technologies that convert energy.

10 questions, free, marked as you go with a worked explanation on every one.

What this covers

A device takes in 150 J and delivers 45 J of useful output. What is its efficiency as a percentage?
What is the ultimate source of the energy stored in fossil fuels?
Which are alternative energy technologies? Select all that apply.
What is a disadvantage of nuclear fission as an energy source?
Why is balancing energy demand against a viable biosphere difficult?
Which action would most reduce a household's energy-related emissions?
A rooftop solar array in Calgary has a total panel area of 20.0 m² and receives sunlight at 800 W/m² around midday. The panels convert 18% of the energy that lands on them into electrical energy. What electrical power does the array produce, in kilowatts?
A coal-fired generating station turns about 35% of the chemical energy in its fuel into electrical energy delivered to the grid. What becomes of the other 65%?
Use the table. What is the LED bulb's efficiency, as a percent?
A car engine is 25 percent efficient and burns fuel that releases 2000 kJ of chemical energy. How many kilojoules are lost rather than turned into useful work?