Question

How far must the mirror M₂ (see Fig. 35.19) of the Michelson interferometer be moved so that 1800 fringes of He-Ne laser light $\mathit{\lambda }\mathbf{=}\mathbf{633}$move across a line in the field of view?

Short answer

We have to move mirror by this distance$5.70\times {10}^{-4}m$ .

Step-by-step solution

Given information

We are given m = 1800,${\lambda }_{air}=633nm=633\times {10}^{-9}$

Calculation

Since,

$y=\frac{m\lambda }{2}$

Whereas y is the mirror move distance.

Hence, we will substitute the given values

$$\begin{gathered} y=\frac{1800\times 633\times {10}^{-9}}{2} \\ y=5.70\times {10}^{-4}m \end{gathered}$$

Hence, we have to move mirror by this distance$5.70\times {10}^{-4}m$ .