1. When a flashlight is left on, its battery eventually "dies." According to the Law of Conservation of Energy, what has happened to the energy that was stored in the battery?
- A. The energy has been destroyed by the chemical reactions inside the battery.
- B. The energy has been converted into light and heat.
- C. The energy has been used up and no longer exists in any form.
- D. The energy has been transferred back to the power grid that charged it.
2. A person eats an apple, then goes for a run. Which of the following describes the primary energy conversions that occur?
- A. Kinetic energy to chemical energy to thermal energy.
- B. Chemical energy to kinetic energy and thermal energy.
- C. Thermal energy to chemical energy to kinetic energy.
- D. Potential energy to kinetic energy to chemical energy.
3. A bouncing ball never returns to its original drop height. According to the Law of Conservation of Energy, why does this happen?
- A. The impact with the ground permanently destroys a small fraction of the ball's total energy.
- B. Energy is converted into sound and heat.
- C. The system is not closed, so energy leaks out into the surrounding atmosphere without changing form.
- D. Potential energy is converted to kinetic energy, but the reverse conversion is not possible.
4. Imagine a perfectly insulated, sealed room containing a running refrigerator. What will happen to the overall temperature of the room over time?
- A. It will decrease.
- B. It will stay the same.
- C. It will increase.
- D. It will fluctuate up and down.
5. If a battery supplies 50 joules of electrical energy to a simple circuit with a light bulb, what must be true about the energy transformation within the battery itself?
- A. The battery created 50 joules of new electrical energy.
- B. The battery converted 50 joules of chemical energy.
- C. More than 50 joules of chemical energy were destroyed.
- D. The battery absorbed 50 joules of heat from the air.
6. A person vigorously shakes a flashlight to power its bulb without batteries. This action demonstrates the transformation of what form of energy into electrical energy?
- A. Chemical energy
- B. Thermal energy
- C. Kinetic energy
- D. Potential energy
7. Which of the following best describes the fundamental principle of how a generator works?
- A. It stores electrical energy that has been generated by an external power source for later use.
- B. It creates new energy from nothing simply by using powerful magnetic fields.
- C. It transforms the energy of motion into electrical energy.
- D. It consumes electrical energy in order to produce mechanical movement for a machine.
8. The process of energy conversion is best described as:
- A. The creation of brand new energy within a closed system to perform work.
- B. The permanent loss of energy as it is used up by a device.
- C. The transformation of energy from one specific type to another.
- D. The transfer of energy between objects without changing its form.
9. A hydroelectric dam produces electricity by first allowing water to fall and turn a turbine. This initial part of the process relies on converting which form of energy into kinetic energy?
- A. Chemical energy
- B. Electrical energy
- C. Potential energy
- D. Thermal energy
10. Based on the principle of energy conversion, why can a hand-cranked radio play music without batteries?
- A. The radio's antenna is specially designed to capture and store ambient energy from surrounding radio waves.
- B. It absorbs heat from the user's hand and efficiently transforms it into the necessary electrical power.
- C. The kinetic energy from turning the crank is transformed into electrical energy.
- D. The crank mechanism mechanically compresses air to vibrate the speaker and produce sound directly.