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

Question

Quizplus · Accepted Answer

The change in the difference of arm lengths is equal to half the wavelength of the light source. So, the change is $400 \mathrm{~nm}/2 = 200 \mathrm{~nm} = 2.0 \times 10^{-4} \mathrm{~mm}$.

Using a Michelson Interferometer and a Light Source Of 400 nm400 \mathrm{~nm}400 nm

Using a Michelson Interferometer and a Light Source Of $400 \mathrm{~nm}$