Astronomy Practice Exam

What is the relationship between energy types?

1. Energy can change type but cannot be created or destroyed.

2. Energy is always fixed and cannot be changed.

3. Energy can be destroyed during a transformation.

4. Energy types can evolve and increase over time.

The correct answer is: Energy can change type but cannot be created or destroyed.

The correct answer is based on the principle of the conservation of energy, which states that energy cannot be created or destroyed; it can only change forms. This means that energy can transform from one type to another — for example, kinetic energy can convert into thermal energy, or chemical energy can turn into electromagnetic energy during various processes like combustion or photosynthesis. This principle is fundamental to understanding various physical processes and systems. For instance, in a hydroelectric dam, gravitational potential energy is converted into mechanical energy as water flows down, and subsequently into electrical energy when that mechanical energy drives a generator. The other options do not align with established scientific principles about energy. The notion that energy is always fixed contradicts the fundamental concept that energy can be transformed. Suggesting that energy can be destroyed during a transformation violates the conservation law; energy can change type but never reduce to nothing. The idea that energy types can evolve and increase over time is misleading, as it implies a creation of more energy rather than a transformation of existing energy.