Radio waves and visible light in vacuum have

Options

A. same velocity but different wavelength
B. continuous emission spectrum
C. band absorption spectrum
D. line emission spectrum

Explanation

To solve the question regarding the properties of radio waves and visible light in a vacuum, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Electromagnetic Waves**:
- Both radio waves and visible light are types of electromagnetic waves. They travel through a vacuum at the same speed, which is the speed of light (denoted as \( c \)).

2. **Speed of Light**:
- The speed of light in a vacuum is constant and is approximately \( 3 \times 10^8 \) m/s. This applies to all electromagnetic waves, regardless of their frequency or wavelength.

3. **Relationship Between Speed, Frequency, and Wavelength**:
- The relationship between the speed of light (\( c \)), frequency (\( f \)), and wavelength (\( \lambda \)) is given by the equation:
\[ c = f \times \lambda \]
- This means that for a given speed, if the frequency increases, the wavelength must decrease, and vice versa.

4. **Comparison of Radio Waves and Visible Light**:
- Radio waves have a lower frequency compared to visible light, which means they have a longer wavelength.
- As we move from gamma rays (high frequency, short wavelength) to radio waves (low frequency, long wavelength), the frequency decreases and the wavelength increases.

5. **Conclusion**:
- Since both radio waves and visible light travel at the same speed in a vacuum but have different wavelengths and frequencies, the correct statement is that they have the same speed but different wavelengths.

### Final Answer:
- Radio waves and visible light in vacuum have the **same speed but different wavelengths**.

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