Which of the following component remains the same when the wave propagates in the medium ?

Options

A. Velocity
B. Frequency
C. Wavelength
D. Angular velocity

Explanation

To solve the question regarding which component remains the same when a wave propagates in a medium, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Components**: The question provides four components: velocity, frequency, wavelength, and angle of velocity. We need to analyze how each of these components behaves when a wave travels through a medium.

2. **Frequency**: Frequency is defined as the number of oscillations or cycles that occur in a unit time. It is determined by the source of the wave and does not change when the wave travels through different media. Therefore, frequency remains constant regardless of the medium.

3. **Velocity**: The velocity of a wave is dependent on the medium through which it is traveling. Different media have different properties (like density and elasticity), which affect the speed of the wave. Hence, the velocity will change when the wave propagates from one medium to another.

4. **Wavelength**: Wavelength is the distance between successive crests (or troughs) of a wave. While it is related to both frequency and velocity (given by the equation \( v = f \lambda \)), it will change when the wave enters a different medium due to the change in velocity. Thus, wavelength is not constant.

5. **Angle of Velocity**: The angle of velocity (or angle of propagation) can also change when a wave enters a different medium, particularly due to refraction. This means that the angle of velocity is not constant.

6. **Conclusion**: After analyzing all the components, we conclude that the only component that remains the same when the wave propagates in the medium is **frequency**.

### Final Answer:
The component that remains the same when the wave propagates in the medium is **frequency**.

---