## Blog entry by Dr. C. Abayaratne

1) why Compensator is placed inclinedly.

*Compensator is placed at a 45 degree angle so that it is parallel to the beam splitter. Compensator is identical to the beam splitter except for the silver coating, The path length through each of these components is equal only if they are placed parallel to one another.*

2)can we use Compensator vertically as shown in figure.(figure is attached to this mail)

__ __*No. Then the path length through each component will not be the same.*

Madam this your exercise for the note

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Exercise: Suppose that the fringe order of the central dark fringe is 100. If you move away from the center, what are the orders of the next three consecutive rings of the fringe pattern? (Hint: Consider the variation of the angle corresponding to fringes as you move away from the center).

__Madam I can not understand problem. __

3)Could you please help me to understand this problem.

Please give me answer for this problem.

*The next 3 orders would be 99, 98 and 97. I just wanted to draw students’ attention to the fact that the fringe order decreases away from the center in the circular fringes obtained from the Michelson Interferometer. (Compare with Newton rings and note the difference.)*