# Let's see the path

Classical Mechanics Level 5

Two mirrors $$M_1$$ and $$M_2$$ make an angle $$\phi$$ with line $$AB$$. A point source $$S$$ is kept at a distance r from the point of intersection of mirrors. A small hemispherical annular mask is kept close to $$S$$ so that no ray emanating from $$S$$ directly reaches the screen kept at a distance $$b$$ from the source. Interference pattern of rays reflected from $$M_1$$ and $$M_2$$ is observed on the screen. The fringe width of this interference pattern is (in micro-meter )

$$\lambda=5000 \mathring { A }$$, $$b=4~m$$, $$r=1~m$$, $$\phi=30^{\circ}$$

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