Complete the statement about the principal of Conservation of Energy.

Energy can be changed for one form to another but the total amount of energy

Conservation of Energy Questions.

Example: A battery releases 100J of energy to a lamp. The lamp releases 80J of energy as light but it also releases heat energy. How much heat energy is released? Answer=20J ( If he total energy input is 100 and 80 is the output as light, that means that 20 J is left as heat 100J-80J=20J)..Now try these questions..

Question. A battery releases 200J of energy to a lamp. the energy is converted to heat and light. 50kJ is given out as heat. How much is released as Light?

A Radio releases 250J of energy 10J is released as heat , How much is released as sound?

A torch battery releases 50J of energy as heat and 240J as light, What is the total energy released from the battery?

The % energy efficiency of an appliance is

In a filament bulb the electical power input is 40W andthe light (Useful) energy output is 4W. What is the % efficiency?

In a modern low energy bulb, the the electrical power input is 12W and the Light (useful) power output is 4W. What is the energy efficiency of this bulb?

look at the last two questions Suggest why modern bulbs are more efficient? (There is more than one correct answer)

This one is harder.. you need to decide what is the 'useful' energy output.

A TV takes in 600J of electrical energy and gives out 300J of light, 240J of sound and 60J of heat energy (be careful here!

(Higher level only)What is the Formula to calculate energy transfer for Kinetic Energy?