d) Double slit experiment

• describe the double slit experiment

• light → passed through a colour filter

  • to make it monochromatic

• then → diffracted through a single slit

• then → diffracted through double slits

  • exit in phase

  • interfere coherently

• on the screen → bright and dark fringes

  • bright fringes = areas of constructive interference

  • dark fringes = areas of destructive interference

• state the formula for the wavelength of light in the double slit experiment

• state the condition required for the formula to be applied

• λ = ax / D

  • wavelength of light (m) = distance between the double slits (m) x distance between two bright fringes (m) / distance from the screen to the double slits (m)

  a ≪ D

• n/a

• n/a

• n/a

• n/a