Which of the following is not shortwave radiation?

Options

A. X-rays
B. Radio waves
C. Ultra-violet rays
D. Cosmic rays

Answer

To determine which of the following is not shortwave radiation, we need to understand the characteristics of shortwave radiation and compare them with the options provided.

### Step-by-Step Solution:

1. **Define Shortwave Radiation**:
Shortwave radiation refers to electromagnetic radiation that has a specific frequency range. For our purposes, shortwave radiation is defined as having a frequency range of 3 megahertz (MHz) to 30 megahertz (MHz).

2. **Identify the Frequency Range of Radio Waves**:
Radio waves, which are a type of electromagnetic radiation, have a much broader frequency range. Specifically, radio waves have frequencies that range from 30 Hertz (Hz) to 300 gigahertz (GHz). This range is significantly different from that of shortwave radiation.

3. **Comparison**:
Since shortwave radiation is defined between 3 MHz and 30 MHz, and radio waves fall outside this range (starting from 30 Hz up to 300 GHz), we can conclude that radio waves do not fit into the category of shortwave radiation.

4. **Conclusion**:
Based on the definitions and frequency ranges, the option that is not shortwave radiation is **radio waves**.

### Final Answer:
**Radio waves** are not shortwave radiation.

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