Consequences of Thermal Energy Transfer Quiz
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5 questions, one answer each
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1. Which of the following is NOT an energy store?
- A. Kinetic energy
- B. Internal thermal energy
- C. Momentum
- D. Chemical energy
2. A ball of mass 2 kg is dropped from a height of 5 m. Calculate its kinetic energy just before it hits the ground. (Take g = 10 m/s²)
- A. 50 J
- B. 100 J
- C. 20 J
- D. 25 J
3. Energy is transferred to a system by three methods. Which of the following is NOT one of these methods?
- A. By forces doing mechanical work
- B. By electrical currents
- C. By conduction of heat only
- D. By electromagnetic waves
4. A motor lifts a 50 kg mass vertically at constant velocity through a height of 2 m. The electrical energy supplied to the motor is 1200 J. Calculate the efficiency of the motor. (Take g = 10 m/s²)
- A. 41.7%
- B. 83.3%
- C. 58.3%
- D. 100%
5. A Sankey diagram shows energy transformations in a power station. 1000 MJ of chemical energy enters the system. 250 MJ is converted to electrical energy and the rest is dissipated as heat. Which statement correctly applies the principle of conservation of energy?
- A. 750 MJ of energy has been destroyed in the process
- B. The total energy output (250 MJ electrical + 750 MJ heat) equals the total energy input of 1000 MJ
- C. Energy has been created by the power station
- D. The 750 MJ of heat represents new energy produced by combustion