Question

A Michelson interferometer operating at a 600nm wavelength has a 2.02-cm-long glass cell in one arm. To begin, the air is pumped out of the cell and mirror M2 is adjusted to produce a bright spot at the center of the interference pattern. Then a valve is opened and air is slowly admitted into the cell. The index of refraction of air at 1.00 atm pressure is 1.00028. How many bright-dark-bright fringe shifts are observed as the cell fills with air? Am My Answers Give Up Submit

Answer 1

Answer:

19

Explanation:

d = Length of cell = 2.02 cm

$\lambda$ = Wavelength = 600 nm

n = Refractive index of air = 1.00028

In the Michelson interferometer the relation of the number of the bright-dark-bright fringe is given by

$\Delta m=\dfrac{2d}{\lambda}(n-1)\\\Rightarrow \Delta m=\dfrac{2\times 2.02\times 10^{-2}}{600\times 10^{-9}}\times (1.00028-1)\\\Rightarrow \Delta m=18.853\approx 19$

The number of bright-dark-bright fringe shifts that are observed as the cell fills with air are 19