Which one of the following statements is true ?

Options

A. The sound waves in air are longitudinal while the light waves are transverse
B. Both light and sound waves in air are longitudinal
C. Both light and sound waves can travel in vaccum
D. Both light and sound waves in air are transverse .

Answer

To determine which statement is true regarding sound and light waves, we can analyze each option provided in the question.

### Step 1: Understanding Sound Waves
- Sound waves are classified as longitudinal waves. This means that the vibrations of the particles in the medium (air, in this case) occur in the same direction as the wave is propagating.
- For example, if the sound wave is moving in the x-direction, the particles of air also vibrate back and forth along the x-axis.

### Step 2: Understanding Light Waves
- Light waves, on the other hand, are classified as transverse waves. In transverse waves, the vibrations occur perpendicular to the direction of wave propagation.
- For instance, if a light wave is traveling in the x-direction, the electric field vectors (which represent the wave) oscillate in the y-direction, while the magnetic field vectors oscillate in the z-direction.

### Step 3: Evaluating the Statements
1. **Statement 1**: "Sound waves in air are longitudinal while light waves are transverse."
- This statement is true based on our understanding of sound and light waves.

2. **Statement 2**: "Both light and sound waves in air are longitudinal."
- This statement is false because light waves are transverse, not longitudinal.

3. **Statement 3**: "Both light and sound waves can travel in vacuum."
- This statement is false because sound waves require a medium to travel and cannot propagate in a vacuum, while light waves can travel in a vacuum.

4. **Statement 4**: "Both light and sound waves in air are transverse."
- This statement is false as sound waves are longitudinal.

### Conclusion
After evaluating all the statements, we can conclude that the first statement is the only true statement: "Sound waves in air are longitudinal while light waves are transverse."

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