Define the law of conservation of energy .

Explanation

**Step-by-Step Text Solution:**

1. **Understanding Energy**: Energy is a fundamental concept in physics that refers to the capacity to do work or produce change. It exists in various forms, such as kinetic, potential, thermal, chemical, and more.

2. **Definition of the Law**: The law of conservation of energy is a principle in physics that states that the total energy of an isolated system remains constant over time. This means that energy cannot be created or destroyed.

3. **Transformation of Energy**: While energy cannot be created or destroyed, it can be transformed from one form to another. For example:
- Electrical energy can be converted into heat energy (like in a toaster).
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