Question

Which combination of two identical prisms can cancel out the dispersion of white light?

• A. When placed inverted with respect to each other.
• B. When placed perpendicular with respect to each other.
• C. When placed at ${60}^{\circ }$ with respect to each other.
• D. It's not possible to cancel out the effect of each other.

Answer 1

The correct option is A When placed inverted with respect to each other.

When two prisms are placed inverted to each other, the first prism causes dispersion of the white ray, whereas the second prism causes the reunification of all colours to again yield the white light.