Diffraction Physics Example 1

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Example 1

easy
Sound waves (λ=1 m\lambda = 1 \text{ m}) pass through a doorway 0.8 m0.8 \text{ m} wide. Do the sound waves diffract significantly? Explain why you can hear someone around a corner.

Solution

  1. 1
    Diffraction is most significant when the wavelength is comparable to or larger than the gap size.
  2. 2
    Here λ=1 m>0.8 m\lambda = 1 \text{ m} > 0.8 \text{ m} (gap width), so significant diffraction occurs.
  3. 3
    The sound waves spread out as they pass through the doorway, which is why you can hear people in other rooms even without a direct line of sight.

Answer

Yes, significant diffraction occurs because λ≥gap width\text{Yes, significant diffraction occurs because } \lambda \geq \text{gap width}
Diffraction is the bending and spreading of waves around obstacles or through gaps. It is most noticeable when the opening or obstacle is similar in size to the wavelength of the wave.

About Diffraction

The spreading of a wave as it passes through a gap or around the edge of an obstacle.

Learn more about Diffraction →

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Example 4 hard

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