Young’s Double Slits Experiment
- Young’s double-slit is made up of two slits ruled on a piece of slide and painted with ‘aquadak’.
- When monochromatic light passes through Young’s double-slit, diffraction of light occurs and two coherent sources (same amplitude, frequency and phase) are produced.
- The two coherent sources will overlap and superpose to produce the effects of constructive and destructive interference.
- Constructive interference generates bright fringes while destructive interference produces dark fringes.
- Fringe size of bright fringes and dark fringes are about similar in size.
- Requirements for the interference pattern to be observable:
- Monochromatic light is used
- The size of the slit needs to be very small
- The distance between the 2 slits must be small (about 0.5mm)
- The distance between fringes increase as
- light with longer wavelength is used
- the 2 slits are closer
- the distance between the double slit and the translucent screen is increased.
- The wavelength of lightwave can be calculated by using the following equation:
Compare to the pattern of single slit experiment
Q & A
What is meant by a monochromatic light?
Monochromatic light is light with only one colour.