Question

Four independent light waves are expressed as $y_{1}=a_{1}sin\omega t,y_{2}=a_{2}sin\omega t,y_{3}=a_{3}cos\omega t$ and $y_{4}=a_{4}sin\left(\omega t + \pi / 3\right).$ The interference is possible between

• A. $1$ and $3$
• B. $1$ and $4$
• C. $3$ and $4$
• D. Not possible at all

Answer 1

Answer: (D)

Independent light waves can never be coherent.