Refraction And Diffraction

Question 0

What’s refraction ?

Answer 0

When a wave crosses the boundary between two substances from (Glass to air, say)it changes direction. When light shines in to the Glass windowpane, some of the light is reflected, but a lot of it passes through the glass and get refracted as it does so. Waves are only refracted if they meet a new medium at an angle. If they’re travelling along the normal i.e. the angle of incidence zero they will change speed, but are not refracted they don’t change direction.

Question 1

What’s diffraction ?

Answer 1

All waves spread out (diffract) at the edges when they pass through a gap or passing an obstacle. The amount of diffraction depends on the size relative to the wavelength of the wave. Narrowing the gap, or the longer the wavelength, the more the way spreadout. America is one that isn’t the same order of magnitude as a wavelength of the wave – i.e. there about the same size. Whether the gap counts as narrow not depends on the way in question. Light has a very small wave length about (0.0005 mm)so it can be diffractive but it needs a really small gap.