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Question 1:

Which of the following is an example of an energy transformation?

A) Burning wood to produce heat
B) Rolling a ball downhill
C) Lifting a weight vertically
D) Pushing a box on a flat surface

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Explanation: The correct answer is A) Burning wood to produce heat. Burning wood is an example of a chemical energy transformation into heat energy. Chemical energy stored in wood is converted to heat energy during the combustion process.

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Question 2:

Which of the following statements is true regarding energy transformations?

A) Energy can be created or destroyed during transformations
B) Energy transformations are always 100% efficient
C) Energy is conserved during transformations
D) Energy transformations violate the laws of thermodynamics

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Explanation: The correct answer is C) Energy is conserved during transformations. Energy transformations involve the conversion of energy from one form to another, but the total amount of energy remains constant. This principle is known as the conservation of energy.

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Question 3:

What is the efficiency of an energy transformation that converts 400 J of input energy into 320 J of useful output energy?

A) 20%
B) 40%
C) 80%
D) 120%

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Explanation: The correct answer is C) 80%. Efficiency is calculated by dividing the useful output energy by the input energy and multiplying by 100%. In this case, (320 J / 400 J) * 100% = 80%.

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Question 4:

Which of the following factors can reduce the efficiency of an energy transformation?

A) Friction
B) Heat loss
C) Incomplete combustion
D) All of the above

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Explanation: The correct answer is D) All of the above. Factors such as friction, heat loss, and incomplete combustion can reduce the efficiency of an energy transformation. These factors result in the dissipation of energy in forms that are not useful for the intended purpose.

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Question 5:

Which of the following energy transformations is an example of an inefficient process?

A) Electric energy to light energy in an incandescent bulb
B) Chemical energy to kinetic energy in a car engine
C) Potential energy to kinetic energy in a roller coaster
D) Nuclear energy to electrical energy in a power plant

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Explanation: The correct answer is A) Electric energy to light energy in an incandescent bulb. Incandescent bulbs are inefficient because they convert a significant portion of the electrical energy into heat energy rather than light energy. This results in wasted energy and lower overall efficiency.