Question

A parallel beam of light from a laser with a wavelength 450 nm, falls on a grating whose slits are 1.28 x 10^-4 cm apart. How far (in cm) is the 1t order bright spot from the center of the pattern on a screen 3.4 m away?

Answer 1

Y_1 = 1.195 m = 119.5 cm

Step-by-step explanation:

For nth order bright fringe, the distance from the center of the pattern is given by :-

`Y_n = (n\lambda D)/(d).`

Where,

n = order of nth bright fringe. = 1

`\lambda =` wavelength of given light =
`450 nm = 450*10-{9} m`

D = distance between the screen and slits. = 3.4 m

and d = separation between the slits.
`= 1.28 *10^(-4) cm =1.28 *10^(-6) m`

`Y_1 = \frac{(1 *450 *10{-9} *3.4)}{(1.28*10{-6})}`

Y_1 = 1.195 m = 119.5 cm