Diffraction
How waves bend and spread around obstacles and openings
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Review - Standing Waves
St.
Mary's Physics
D. Diffraction – the spreading out of a wave into the region behind an obstacle
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Wave/Slit/Diffraction
Why does the amount of diffraction increase
Review - Which slit will create the most diffraction?
Enrichment
More on Diffraction
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Check Your Understanding
5 quick questions — pick an answer to see if you’re right.
1. Diffraction is
2. The amount of diffraction through an opening depends on
3. Light of wavelength 500 nm passes through a slit. Which slit width produces the MOST diffraction?
4. If the width of a slit is made smaller (but still about the size of the wavelength), the amount of diffraction
5. You can hear a friend talking around a corner but can't see them. The best explanation is that sound
Hearing Around Corners
A student in the hallway can clearly hear a teacher talking inside a classroom through the open doorway, but cannot see the teacher, who is out of the line of sight. The doorway is about 1 m wide.
Which statement best explains this?
▶ Want a challenge? Open 6 more Regents-style questions (harder · mixed formats)
Challenge score: 0 / 6
C1. A teacher’s voice includes a 170-Hz sound. The speed of sound in air is 340 m/s. Substitute numerical values into a mathematical representation that can be used to determine the wavelength of this sound. Then calculate the wavelength.
C2. AM radio waves (wavelength ≈ 300 m) can be received behind hills where FM signals (wavelength ≈ 3 m) cannot. Why?
C3. Water waves in a ripple tank pass through a gap in a barrier. Place a check mark in two boxes to indicate changes that would increase the spreading (diffraction) of the waves beyond the gap.
C4. A student makes the following claim.
Place a check mark in either the Support or Refute box. Justify your response using a mathematical relationship.
C5. When a wave diffracts through an opening, which property changes?
C6. People living behind a highway noise barrier hear the low-pitched rumble of trucks much more than the high-pitched hiss of tires. Explain why, and propose one design change to the barrier along with one trade-off of that change.