For a radio wave reaching the ionised medium

Options

A. will bend away from normal
B. will bend towards normal
C. will bend follow a straight-path
D. None of these

Explanation

To solve the question regarding the behavior of a radio wave when it reaches an ionized medium, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Mediums**:
- Identify the two mediums involved: the first is the ionized medium (which can be considered as a rarer medium) and the second is the non-ionized medium (which can be considered as a denser medium).

2. **Determine the Nature of the Wave**:
- A radio wave is a type of electromagnetic wave. When it travels from one medium to another, its speed and direction can change depending on the properties of the mediums.

3. **Apply Snell's Law**:
- Snell's Law states that \( n_1 \sin(\theta_1) = n_2 \sin(\theta_2) \), where \( n_1 \) and \( n_2 \) are the refractive indices of the two mediums, and \( \theta_1 \) and \( \theta_2 \) are the angles of incidence and refraction, respectively.

4. **Identify the Refractive Indices**:
- The denser medium (non-ionized) has a higher refractive index compared to the rarer medium (ionized). Therefore, \( n_1 > n_2 \).

5. **Analyze the Angle of Refraction**:
- According to Snell's Law, when a wave travels from a denser medium to a rarer medium, it bends away from the normal. This means that the angle of refraction \( \theta_2 \) will be greater than the angle of incidence \( \theta_1 \).

6. **Conclusion**:
- Since the radio wave is moving from a denser medium (non-ionized) to a rarer medium (ionized), it will bend away from the normal. Thus, the correct answer is: **A. Will bend away from the normal**.