Educator

Interference of Light Waves

• Interference between two sources will be observed if the sources are
1. Coherent (maintain a constant phase difference)
2. Monochromatic (both sources have the same single wavelength)
• To have coherent sources, use a single source with 2 slits.
• In Young’s double slit experiment, bright and dark fringes are obtained on a screen. The bright fringes result from constructive interference, whereas dark fringes result from destructive interference.
• Young’s experiment established conclusively the wave nature of light: waves interfere, particles don’t.