a convex lens of focal length 25cms was cut along the diameter into two identical halves and then was again set leaving a thin gap of width a= 0.1cm as shown. A narrow slit emtting monochromatic light of λ = 0.6μm was placed at the focus of the lens. A screen is placed behind the lens at a distance 50cm
the width of the interference fringes will be ?
the total number of fringes obtained will be ?
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1 Answers
1for both the lens you will get one image each of the source and as you can find out the distance betwen them
=2*h where h is the height of image in any case (by height = distance from the respective principal axis)
this you can take as d
further you will get the distance D from the screen which will be the distance from the image s
so after that you apply regular formula and get the answers
one more point S1 and S2 will not be the ones shown in the diagram they will be on the other side of the lens
