Q.1
A wind turbine generates 100 joules of electricity from a gust of wind which has 300 joules of energy. How efficient is the turbine?
  • 10%
  • 33%
  • 50%
  • 66%
Q.2
During an energy transfer, only part of it may be usefully transferred. What happens to the remainder of the unused energy?
  • It's wasted
  • All the energy is all transferred and used successfully
  • It is converted into carbon
  • It becomes a gas
Q.3
What happens to wasted energy?
  • It decomposes into the ground
  • It becomes hot
  • No energy is ever wasted
  • It is transferred into its surroundings
Q.4
What cannot be done to energy?
  • Created or destroyed
  • Dissipated
  • Transferred
  • Stored
Q.5
A solar panel is 20% efficient at converting light energy into electricity. If it generates 200 joules of electrical power, how much power is wasted?
  • 500 J
  • 750 J
  • 800 J
  • 1000 J
Q.6
What can be done to energy?
  • It can be transferred
  • It can be stored
  • It can be dissipated
  • All of the above
Q.7
Which formula can be used to calculate the percentage of energy transferred by a device?
  • Energy Transferred = Useful Energy Output⁄Total Energy Input x 100
  • Energy Transferred = Total Energy Input⁄Useful energy output x 100
  • Energy Transferred = Useful Energy Output⁄Total Energy Input x 10
  • Energy Transferred = Total Energy Input⁄Useful energy output x 10
Q.8
Calculate the efficiency of a heater which can convert 700 joules of chemical energy into 175 joules of heat energy.
  • 10%
  • 25%
  • 35%
  • 50%
Q.9
Which formula can be used to calculate the percentage of power transferred by a device?
  • Power Transferred = Useful Power Output⁄Total Power Input x 100
  • Power Transferred = Total Power Input⁄Useful Power Output x 100
  • Power Transferred = Useful Power Output⁄Total Power Input x 10
  • Power Transferred = Total Power Input⁄Useful Power Output x 10
Q.10
An LED converts around 80% of the energy supplied to it into light. How much energy is converted into light if a total of 50 J is supplied to it?
  • 30 J
  • 40 J
  • 50 J
  • 60 J
0 h : 0 m : 1 s