Question 128: Wave Optics

Question

Interference fringes are observed on a screen
by illuminating two thin slits 1 mm apart with a
light source ($$\lambda $$ = 632.8 nm). The distance
between the screen and the slits is 100 cm. If
a bright fringe is observed on a screen at a
distance of 1.27 mm from the central bright
fringe, then the path difference between the
waves, which are reaching this point from the
slits is close is

Accepted Answer

y = $${{nD\lambda } \over d}$$
$$ \Rightarrow $$ n = $${{yd} \over {D\lambda }}$$
= $${{1.27 	imes {{10}^{ - 3}} 	imes {{10}^{ - 3}}} \over {1 	imes 632.8 	imes {{10}^{ - 9}}}}$$ = 2
Path difference $$\Delta $$x = n$$\lambda $$
= 2 $$ 	imes $$ 632.8 nm
= 1265.6 nm
= 1.27 $$\mu $$m

Answer

1.27 $$\mu $$m

Answer

2.05 $$\mu $$m

Answer

2.87 nm

Answer

2 nm

Wave Optics

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