Question

If three identical prisms are combined, is it possible to pass a beam that emerges undeviated? Undispersed?

Answer 1

If three identical prisms are combined, it is not possible to pass a beam that emerges undeviated and undispersed.

• This is not possible even if the prisms are combined having their refractive angle reversed with respect to each other.

• There will be at least some kind of deviation and dispersion.

• That deviation and dispersion will be equal to the deviation and dispersion produced by any single prism.

Answer 2

If three identical prisms are combined, it is not possible to pass a beam that emerges undeviated and undispersed.

Explanation:

No, It is not possible even when prisms are inverted in relation to each other with their refractive angle. There will be at least one net deviation and dispersion equal to the dispersion and deviation that a single prism produces.

For example,

When you pass a white light, it will be reflected in seven different colors, but if you pass all seven light into a prism, it will pass through it and turn white.              

Thus, it is not possible to pass a beam that emerges undeviated and undispersed.