# In a Double-slit Experiment the Angular Width of a Fringe is Found to Be 0.2° on a Screen Placed 1 M Away. the Wavelength of Light Used is 600 Nm. What Will Be the Angular Width of the Fringe If the Entire Experimental Apparatus is Immersed in Water? Take Refractive Index of Water to Be 4/3. - Physics

In a double-slit experiment the angular width of a fringe is found to be 0.2° on a screen placed 1 m away. The wavelength of light used is 600 nm. What will be the angular width of the fringe if the entire experimental apparatus is immersed in water? Take refractive index of water to be 4/3.

#### Solution

Distance of the screen from the slits, D = 1 m

Wavelength of light used, lambda_1 = 600 nm

Angular width of the fringe in air theta_1 = 0.2^@

Angular width of the fringe in water = theta_2

Refractive index of water, mu = 4/3

Refractive index is related to angular width as:

mu = theta_1/theta/2

theta_2 = 3/4 theta_1

= 3/4 xx 0.2 = 0.15

Therefore, the angular width of the fringe in water will reduce to 0.15°.

Is there an error in this question or solution?

#### APPEARS IN

NCERT Class 12 Physics Textbook
Chapter 10 Wave Optics
Q 7 | Page 383