Efficiency & Energy Resources Quiz
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5 questions, one answer each
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1. How is efficiency calculated?
- A. Total energy supplied divided by useful energy transferred
- B. Useful energy transferred divided by total energy supplied
- C. Useful energy transferred multiplied by total energy supplied
- D. Total energy supplied minus useful energy transferred
2. A motor is supplied with 80 J of energy and usefully transfers 60 J as kinetic energy. What is its efficiency?
- A. 60%
- B. 75%
- C. 80%
- D. 133%
3. Which of these is a renewable energy resource?
- A. Coal
- B. Natural gas
- C. Tides
- D. Nuclear fuel
4. Which method would most directly increase the efficiency of a machine with moving parts?
- A. Increasing the total energy supplied
- B. Lubricating the moving parts to reduce friction
- C. Painting the machine a darker colour
- D. Increasing the machine's mass
5. A country wants to reduce its reliance on fossil fuels for electricity generation. Which combination of changes best reflects the general global trend described in the specification?
- A. Increased use of coal and decreased use of wind power
- B. Increased use of renewable resources and decreased reliance on fossil fuels
- C. No change in the balance of energy resources used
- D. Complete replacement of all energy resources with nuclear power only