1. The problem statement, all variables and given/known data i know that for intefernece of light waves to occur , the light waves must be coherent. How if two light waves are incoherent? according to my notes, inteference can still occur if waves are not coherent, but the position of pattern will shift constantly with time to give a uniform illumination. 2. Relevant equations 3. The attempt at a solution In my opinion , the constructive intefrence and destructive inteference occur too fast , namely countless times in a second . So our eyes cant detect it. Thus , only 'bright region' will be obersved all the time. please correct me if i am wrong.