Which one of the following is not the unit of energy?

Options

A. Joule
B. Newton metre
C. Kilowatt
D. Kilowatt hour

Explanation

To solve the question "Which one of the following is not the unit of energy?", we will analyze each option provided and determine whether it is a unit of energy or not.

### Step-by-Step Solution:

1. **Identify the Options**:
Let's assume the options provided are:
- A) Joule
- B) Newton meter
- C) Kilowatt
- D) Kilowatt hour

2. **Analyze Each Option**:
- **Option A: Joule**
- The Joule (J) is the SI unit of energy. It is defined as the amount of energy transferred when a force of one newton is applied over a distance of one meter.
- **Conclusion**: Joule is a unit of energy.

- **Option B: Newton meter**
- The Newton meter (N·m) is also a unit of work and energy. Since work is defined as force multiplied by displacement (Work = Force × Distance), and force is measured in Newtons and distance in meters, we conclude that Newton meter is equivalent to Joules.
- **Conclusion**: Newton meter is a unit of energy.

- **Option C: Kilowatt**
- The Kilowatt (kW) is a unit of power, not energy. Power is defined as the rate at which work is done or energy is transferred over time.
- **Conclusion**: Kilowatt is not a unit of energy.

- **Option D: Kilowatt hour**
- The Kilowatt hour (kWh) is a unit of energy. It represents the amount of energy consumed when a power of one kilowatt is used for one hour. It can be calculated as Energy = Power × Time.
- **Conclusion**: Kilowatt hour is a unit of energy.

3. **Final Conclusion**:
Based on the analysis, the only option that is not a unit of energy is **C) Kilowatt**.