The velocity of sound in a gas depends on:

Options

A. wavelength only
B. density & elasticity of gas
C. intensity only
D. amplitude & frequency

Explanation

To determine what the velocity of sound in a gas depends on, we can analyze the factors involved in sound propagation. Here’s a step-by-step solution:

### Step-by-Step Solution:

1. **Understanding Sound Propagation**:
- Sound travels through different media (solids, liquids, gases) and its speed can vary based on the properties of the medium.

2. **Newton-Laplace Equation**:
- The velocity of sound in a gas can be described by the Newton-Laplace equation:
\[ V = \sqrt{\frac{K}{\rho}} \]
- Where:
- \( V \) = velocity of sound
- \( K \) = bulk modulus (a measure of the elasticity of the gas)
- \( \rho \) = density of the gas

3. **Identifying Key Factors**:
- From the equation, we see that the velocity of sound \( V \) depends on:
- **Density (\( \rho \))**: The mass per unit volume of the gas.
- **Elasticity (\( K \))**: The ability of the gas to return to its original shape after being compressed.

4. **Eliminating Other Options**:
- **Wavelength**: While wavelength is related to frequency and velocity, it does not directly affect the velocity of sound in a gas.
- **Intensity**: This is related to the energy of the sound wave but does not affect its speed.
- **Amplitude and Frequency**: These are characteristics of the sound wave but do not influence the speed of sound in the medium.

5. **Conclusion**:
- Therefore, the velocity of sound in a gas primarily depends on the **density and elasticity of the gas**.

### Final Answer:
The velocity of sound in a gas depends on **density and elasticity** of the gas.

---