Question

When a movable mirror of michelson interferometer is moved through a distance of 0.030 mm under illumination of wavelength 6000 angstrom, the number of displaced fringes is

Answer 1

$d=\frac {m\lambda}{2}$. Therefore,

$0.030=300m$

$0.030mm=\frac{m\times6000}{2}$

Thus: $m=0.00001$

The number of fringes is 0.00001