Using a Michelson interferometer and a light source of 400 nm, a change from bright to dark indicates a change in the difference of arm lengths of A) 2.0 × 10^-4 mm. B) 4.0 × 10^-4 mm. C) 3.0 × 10^-4 mm. D) 1.0 × 10^-4 mm.

Question

Quizplus · Accepted Answer

A change from bright to dark in a Michelson interferometer indicates a path difference of half the wavelength of the light used. Since the wavelength given is 400 nm (4.0 × 10^-7 m or 4.0 × 10^-4 mm), half of this value is 2.0 × 10^-4 mm or 2.0 × 10^-7 m, which is option D when correctly interpreted from scientific notation.

Using a Michelson Interferometer and a Light Source of 400