Stand behind a wall and you can still hear someone speaking, but you cannot see them. Sound waves are long enough to bend around the edge; light waves are far too short. Whether a wave spreads depends on how its wavelength compares with the gap or obstacle.
Diffraction is the spreading of waves through a gap or around an edge. The effect depends on the ratio of the gap width to the wavelength: spreading is strongest when the gap is comparable to the wavelength, and for a given gap, longer wavelengths diffract more.
Diffraction is the spreading of waves as they pass through a gap or around an edge; it is greatest when the gap width is comparable to the wavelength.
For a fixed gap, a longer wavelength diffracts more than a shorter one.
Change the gap width and the wavelength and watch how much the waves spread beyond the gap.
Four quick checks. Each correct answer earns XP and lights this skill on your star map.
Diffraction is the...
Diffraction through a gap is strongest when the gap is...
For the same gap, which wave diffracts more?
A gap much wider than the wavelength produces...
Whether a wave spreads a lot or a little comes down to comparing the gap with the wavelength.
It is the ratio of gap to wavelength that matters, not the absolute size of the gap. A gap is only effectively narrow if it is small compared with the wavelength, so the same gap can diffract long waves strongly and short waves hardly at all.
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Radio waves bend around a hill but light does not, mainly because radio waves have...
To produce the most diffraction through a gap, the gap should be made...
As a gap is widened until it is much greater than the wavelength, the diffraction...
That completes the general-waves group. Light is next.