Which of the following best describes the difference between energy and power?

• A. Energy and power are two names for the same physical quantity.
• B. Energy is the capacity to do work, while power is the rate at which work is done or energy is transferred.
• C. Power is the total amount of work done, while energy is the rate at which work is done.
• D. Energy and power are both measured in $J$ (joules).

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the definition of energy. Energy is the capacity to do work or to cause change. It is a scalar quantity measured in joules (J).
2. Step 2: Understand the definition of power. Power is the rate at which work is done or energy is transferred over time. It tells us how quickly energy is used or produced.
3. Step 3: Recognize the difference in units. While energy is measured in joules (J), power is measured in watts (W), where 1 watt equals 1 joule per second (1 W = 1 J/s).
4. Step 4: Express the relationship mathematically. Power can be written as \(\text{Power} = \frac{\text{Energy}}{\text{Time}}\) or \(P = \frac{E}{t}\), showing that power depends on how fast energy is used.
5. Step 5: Summarize the distinction. Energy is the total amount of work that can be done, while power is how fast that work is done or energy is transferred.