Question

Newton’s rings are observed with two different media between the glass surface. The nth rings have diameters as 10:7; Find the ratio of the refractive indices of the two media

Answer 1

Answer on Question #47769, Engineering, Other

Newton's rings are observed with two different media between the glass surfaces. The nth rings have diameters as 10:7; Find the ratio of the refractive indices of the two media

Solution:

Newton's rings is a phenomenon in which an interference pattern is created by the reflection of light between two surfaces—a spherical surface and an adjacent flat surface.

For a dark ring viewed by reflection:

$$n \lambda = \frac {\mu r _ {n} ^ {2}}{R}$$

where $n = 0, 1, 2, 3, \text{etc}$, $r_n$ is the radius of the $n$th ring and $\mu$ is refractive index.

Thus,

$$r _ {n} = \frac {\overline {{n \lambda R}}}{\mu}$$

In our case,

$$\frac {r _ {n 1}}{r _ {n 2}} = \frac {\overline {{\mu_ {2}}}}{\mu_ {1}} = \frac {1 0}{7}$$

Thus,

$$\frac {\mu_ {2}}{\mu_ {1}} = \frac {1 0 0}{4 9}$$ $$\frac {\mu_ {1}}{\mu_ {2}} = \frac {4 9}{1 0 0} = 0. 4 9$$

Answer: $\frac{\mu_1}{\mu_2} = \frac{49}{100} = 0.49$

http://www.AssignmentExpert.com/