Energy cannot be...
When a lightbulb warms up what is the wasted energy?
How could you reduce the amount of air resistance acting on an object?
Which equipment would you use to measure 93ml of water?
A child runs 1200m in 260 seconds. What is their speed?
Challenge: name the 8 energy stores.
Define Efficiency
State the equation used to calculate efficiency
Name the two ways efficiency can be written
Name the energy transferred to the surroundings
What is the correct definition of efficiency?
State the equation used to calculate efficiency
If a kettle has an efficiency of 0.875, what is this efficiency written as a percentage?
When energy has been transferred to the surroundings it has…
400 Joules of energy goes in and 350 Joules is transferred to thermal energy therefore only ………….. Joules of sound is wasted
10,000 Joules of kinetic energy goes in and 8,000 Joules of energy is transferred to electrical and therefore only ……………Joules of heat energy is dissipated.
Calculate the efficiency, as a percentage, of a speaker that uses 300 J which it radiates as 96 J of sound energy.
100J of energy is transferred electrically to a filament bulb, of which 45J are radiated usefully as light. Calculate its efficiency as a percentage.
250J of energy is transferred electrically to a filament bulb, of which 150J are radiated as light and 100J stored thermally in the filament. Calculate its efficiency as a percentage.
2.5kJ of energy is transferred electrically to a filament bulb. The efficiency of the lamp is 0.4. Calculate how much energy is usefully transferred
To calculate efficiency you divide ________ by __________.
If an energy transfer is very efficient that means that a (large/small) amount of energy is being transferred usefully & a (large/small) amount is dissipated.
3)If a transfer has an efficiency of 0.75, we can also write this as being ___________% efficient.