Which of these are forms of energy waiting to be turned into one of the other forms? (Tick all that apply)
Thermal
Chemical potential
Gravitational potential
Kinetic
Electrical
Light
Elastic potential
Nuclear
Sound
What is the principle of the conservation of energy?
Energy can never be created or destroyed; it can only be converted from one form to another.
Energy can be created or destroyed; it can also be converted from one form to another.
A light bulb has a total energy input of 200J. 190J of this is wasted energy. Work out the energy efficiency.
10%
5%
90%
Draw a Sankey diagram for a candle which wastes most of its energy as heat.
Describe the energy transfer in this picture.
kinetic ---> electrical
electrical ---> sound ---> light
gravitational potential ---> kinetic ---> electrical
gravitational potential ---> electrical ---> sound
Tick all of the true statements.
A device which transfers one form of energy into another is called a transducer.
Energy is normally wasted as heat and sound.
Wasted energy dissipates into the surroundings.
Dissipated energy cannot be re-used.
Which type of heat energy transfer only takes place in fluids and involves warmer, less dense regions of fluid moving upwards and being replaced by colder, sinking fluids?
Conduction
Convection
Radiation
All types of energy require particles to be transferred.
Which of these loses energy more quickly?
A bright, shiny surface
A dull, black surface
Which features of a vacuum flask prevent heat loss by conduction?
A thin vacuum between the walls
Silvered walls
Cork or plastic stopper
Find the work done by a car driving at a force of 500N 200m down a road.
1000J
5000J
700J
300J
What is power?
Power is the rate of doing work.
Power = work done x time taken
Power = work done/time taken
How fast does a stone weighing 4kg fall from a height of 200m?
28 m/s
800 m/s
63 m/s
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