If a wave gets refracted into a denser medium , then which of the following is true ?

Options

A. wavelength ,speed and frequency decreases
B. wavelength increases ,speed decreases and frequency remains constant
C. wavelength and speed decreases but frequency remains constant .
D. wavelength ,speed and frequency increases

Explanation

To solve the problem of how a wave behaves when it is refracted into a denser medium, we need to understand the relationship between speed, wavelength, and frequency of the wave.

### Step-by-Step Solution:

1. **Understanding the Wave Properties**:
- A wave has three key properties: speed (v), wavelength (λ), and frequency (f). The relationship between these properties is given by the equation:
\[ v = f \cdot \lambda \]

2. **Identifying the Medium Change**:
- When a wave travels from a less dense medium (like air) to a denser medium (like water or glass), it undergoes refraction.

3. **Effect on Speed**:
- In a denser medium, the speed of the wave decreases. This is a fundamental property of wave behavior; waves travel slower in denser materials.

4. **Effect on Frequency**:
- The frequency of the wave is determined by the source of the wave and remains constant when the wave transitions between media. Therefore, \( f \) does not change.

5. **Effect on Wavelength**:
- Since the speed of the wave decreases and the frequency remains constant, we can use the wave equation \( v = f \cdot \lambda \) to determine the change in wavelength.
- Rearranging the equation gives us:
\[ \lambda = \frac{v}{f} \]
- Since \( v \) decreases and \( f \) remains constant, \( \lambda \) must also decrease.

6. **Conclusion**:
- Therefore, when a wave refracts into a denser medium, the speed decreases, the wavelength decreases, and the frequency remains constant. The correct answer is option 3: "Wavelength and speed decrease, but frequency remains constant."