Question 403: Wave Optics

Question

In a Young's double slit experiment, a student observes 8 fringes in a certain segment of screen when a monochromatic light of 600 nm wavelength is used. If the wavelength of light is changed to 400 nm, then the number of fringes he would observe in the same region of the screen is

Accepted Answer

$$\beta  = {{\lambda D} \over d}$$
Let length of segment of screen = l
$$ \Rightarrow l = 8{\beta _1} = {{8{\lambda _1}D} \over d}$$ ..... (1)
and $$  l = n{\beta _2} = {{n{\lambda _2}D} \over d}$$ .... (2)
from (1) and (2)
$$8{\lambda _1} = n{\lambda _2}$$
8(600 nm) = n(400 nm)
n = 12

Answer

6

Answer

8

Answer

9

Answer

12

Wave Optics

In a Young's double slit experiment, a student observes 8 fringes in a certain segment of screen when a monochromatic light of 600 nm wavelength is used. If the wavelength of light is changed to 400 nm, then the number of fringes he would observe in the same region of the screen is

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