A Michelson interferometer uses light from a sodium lamp. Sodium atoms emit light having wavelengths 589.0 nm and 589.6 nm. The interferometer is initially set up with both arms of equal length (L1=L2), producing a bright spot at the center of the interference pattern. How far must mirror M2 be moved so that one wavelength has produced one more new maxima than the other wavelength?

51793 bright-dark-bright fringe shifts are observed when the mirror M2 moves through 1.7cm

Explanation:

The number of maxima appearing when the mirror  moves through distance \Delta L is given as follows,

Here,

= is the distance moved by the mirror M

is the wavelenght of the light used?

= 0.017m

Therefore, 51793 bright-dark-bright fringe shifts are observed when the mirror M2 moves through 1.7