Diffraction is easily noticeable for sound waves than for light waves because sound waves

Options

A. Are high energy waves
B. Are low intensity waves
C. Have longer wavelength
D. Are mechanical in nature

Answer

To solve the question regarding why diffraction is more noticeable for sound waves than for light waves, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Diffraction**:
- Diffraction is the bending of waves around obstacles and the spreading of waves when they pass through small openings. The extent of diffraction depends on the wavelength of the wave.

2. **Comparing Wavelengths**:
- To understand why diffraction is more noticeable for sound waves, we need to compare the wavelengths of sound and light waves.
- The wavelength (\( \lambda \)) of a wave can be calculated using the formula:
\[ \lambda = \frac{v}{f} \]
where \( v \) is the speed of the wave and \( f \) is the frequency.

3. **Calculating Wavelength of Light**:
- The speed of light (\( c \)) is approximately \( 3 \times 10^8 \) m/s.
- For visible light, let's take a frequency (\( f \)) of \( 5.46 \times 10^{14} \) Hz.
- Using the formula:
\[ \lambda_{\text{light}} = \frac{c}{f} = \frac{3 \times 10^8 \text{ m/s}}{5.46 \times 10^{14} \text{ Hz}} \approx 5.49 \times 10^{-7} \text{ m} \approx 550 \text{ nm} \]

4. **Calculating Wavelength of Sound**:
- The speed of sound in air (\( v \)) is approximately \( 340 \) m/s.
- Let's take a frequency (\( f \)) of \( 3500 \) Hz.
- Using the formula:
\[ \lambda_{\text{sound}} = \frac{v}{f} = \frac{340 \text{ m/s}}{3500 \text{ Hz}} \approx 0.097 \text{ m} \approx 9.7 \text{ cm} \]

5. **Comparing Wavelengths**:
- From our calculations:
- Wavelength of light: \( 550 \text{ nm} \) (or \( 0.00055 \text{ m} \))
- Wavelength of sound: \( 9.7 \text{ cm} \) (or \( 0.097 \text{ m} \))
- Since the wavelength of sound is significantly longer than that of light, sound waves will diffract more noticeably around obstacles.

6. **Conclusion**:
- The primary reason diffraction is more noticeable for sound waves than for light waves is that sound waves have a longer wavelength compared to light waves. Therefore, the correct answer is that sound waves have a longer wavelength.