10 minutes maximum! Can you do it in 5?

1. Which of these is used to calculate the efficiency of an energy transfer or shift?

A. useful energy output
energy input
   
B. energy input
useful energy output
   
C. energy input
wasted energy output
   
D. wasted energy output
energy input

 
Q2-4. This diagram shows the energy transfer as a skateboarder rolls downhill:

 

sankey diagram for skateboard

 2. What is the percentage efficiency of this transfer of energy?

  • A. 600%
  • B. 70%
  • C. 30%
  • D. 1400%

3. What form of energy is the wasted energy 'X' likely to be?

  • A. Elastic energy stored in the skateboard.
  • B. Chemical energy in the muscles.
  • C. Wind energy from movement.
  • D. Thermal energy from friction.

4. The energy in 'X' can be given as a value or as a percentage. Which of these is correct?

Energy in X (J) Energy in X (%)
A
 600 30
B
 1400 70
C
 30 600
D
 70 1400

 
5-7. This diagram shows the efficiency of a solar panel: solar panel
Sankey diagram for a solar panel

5. What does the 'W' represent in the measurment '40 W' in the diagram?

  • A. Work Done
  • B. Weight
  • C. Wasted energy
  • D. Watts

6. What is the power input to the panel?

  • A. 40 W
  • B. 80 W
  • C. 120 W
  • D. 160 W

7. What is the percentage efficiency of this solar panel?

  • A. 75 %
  • B. 67 %
  • C. 33 %
  • D. 25 %

8. "Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed."

This is called the law of..

  • A. transfer of energy.
  • B. creation of energy.
  • C. conversion of energy.
  • D. conservation of energy.

9&10. A wave power generator is sold with the following specifications:

Typical Power Output: 0.2 kW

Efficiency : 20%

9. 0.2 kW is the same as...

  • A. 0.0002 W
  • B. 20 W
  • C. 200 W
  • D. 2000 W

10. The typical power input to the generator is:

  • A. 1 kW
  • B. 4 kW
  • C. 0.01 kW
  • D. 0.04 kW