Question

The second order bright line appears 0.50 cm from the center bright line when a double slit grating is used. The distance between the slits is 0.25 mm and the screen is 1.20 m from the grating. Find the wavelength of the light.

Answer 1

Distance of nth bright fringe from center is given by :

`y = (n\lambda D)/(d)`

Here, D is distance between screen and slit.

d is distance between two slits.

Now, wavelength is written as :

`\lambda = (yd)/(nD)\\\\\lambda = (0.005* 0.25 * 10^(-3))/(2* 1.2)\\\\\lambda = 5.208* 10^(-7) m = 520.8 \ nm`

Hence, this is the required solution.