What happens during diffraction?
What happens during diffraction?
- When waves pass through two slits, they create two sets of waves which can interfere with each other.
- It creates a pattern of alternating bright and dark fringes on the screen.
- The central bright fringe is the brightest, and the fringes get less bright as you move away from the centre.
- The bright fringes are equally spaced.
How it works
- They interfere constructively when the peaks of both of the waves line up.
- That happens when the phase difference between the two
waves is a multiple of
2\pi , and when the path difference between the two waves is a multiple of one wavelength (\lambda ). - The constructive interference creates the bright fringes.
- That happens when the phase difference between the two
waves is a multiple of
- They interfere destructively when the peaks of one wave line up with the
troughs of the other wave
- That happens when the phase difference between the two waves is not a
multiple of
2\pi , and when the path difference between the two waves is not a multiple of one wavelength (\lambda ). - It will produce dark fringes on the screen.
- That happens when the phase difference between the two waves is not a
multiple of
- The further away the fringe is from the centre, the larger the path difference is between the waves, and so the fringes will be less bright (for constructive interference).