Answer:
Step-by-step explanation:
In Michelson interferometer , two light waves from different directions are made to overlap so that fringes are formed on the screen due to interference . In it, two monochromatic and coherent light are made to overlap which have some path difference or phase difference. They form dark and bright fringes .
Now when a match stick is lit in the path of a wave , the fringes will disappear and an general illumination will be observed on the screen as the light from the lit match stick will not be coherent . Incoherent light can not form stable fringes.