The power of which one of the following expressed in terms of magnitude on a se called the Richter Scale ?

Options

A. Lightning
B. Cyclone
C. Tsunami
D. Earthquake

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which phenomenon's power is expressed in terms of magnitude on the Richter Scale.

2. **Identifying the Options**: The options given are:
- Lightning
- Cyclone
- Tsunami
- Earthquake

3. **Reviewing the Richter Scale**: The Richter Scale is specifically designed to measure the magnitude of earthquakes. It quantifies the amount of energy released during an earthquake.

4. **Analyzing Each Option**:
- **Lightning**: This is a natural electrical discharge and is not measured on the Richter Scale.
- **Cyclone**: This is a weather phenomenon and is measured using different scales, such as the Saffir-Simpson scale, not the Richter Scale.
- **Tsunami**: This is a series of ocean waves caused by disturbances such as earthquakes, but it is not directly measured by the Richter Scale.
- **Earthquake**: This is the only phenomenon among the options that is measured using the Richter Scale.

5. **Conclusion**: Based on the analysis, the power expressed in terms of magnitude on the Richter Scale is that of an **earthquake**.

**Final Answer**: The power of an earthquake is expressed in terms of magnitude on a scale called the Richter Scale.

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