Question

A Young's double slit experiment is performed with white light.

• A. The central fringe will be white.
• B. There won't be a completely dark fringe.
• C. The fringe next to the central fringe will be red.
• D. The fringe next to the central fringe will be violet.

Answer 1

Answer: (A), (B), (D)

The central fringe will be white.
The fringe next to the central fringe will be violet.
There won't be a completely dark fringe.

If a white light is used in the double slit experiment, the different colours will be split up on the viewing screen according to their wavelengths and central fringe will be white.
The violet end of the spectrum (with the shortest wavelengths) is closer to the central fringe, with the other colours being further away in order.