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

Answer:

Y_1 = 1.195 m = 119.5 cm

Explanation:

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

$Y_n = \frac{n\lambda D}{d}.$

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