Physics P1- Energy Transfer and Efficiency

An easy way to remember all 9 energy types is:

Most Kids Hate Learning GCSE Energy Names

Magnetic
Kinetic
Heat
Light
Gravitational potential
Chemical
Sound
Electrical
Elastic potential
Nuclear

(Potential and chemical energy are forms of stored energy, basically waiting to be changed into one of the other forms).

Efficiency is calculated using the following equation:
Efficiency= useful energy output
                 ----------------------------    (if you need as a percentage, you x100)           
                    total energy input

Here is a question to make sure you know how to use the formula:

• The total energy input of a TV is 220J, the light energy is 5J, the heat energy is 213J and the sound energy is 2J, what is the efficiency of the TV?
• (light, heat and sound are all output energy)
  ANSWER:
  We know that the total input energy is 220J.

• To find out the total output energy, we need to add all of the output's together, this adds to 220J. Now we can put these numbers in the equation:
  efficiency= 220
                   -----    =1.
                   220
  By making it into a precentage (x100) we know that the TV is 100% efficient! (Not every TV is this efficient! It was just an example!)