Question

In Newton’s rings experiment with two different media between the glass surfaces, the nth rings have diameters as 10:7. The ratio of the refraction indices of two media are:

• A. \( 7:10 \)
• B. \( 49:100 \)
• C. \( 10:7 \)
• D. \( 100:49 \)

Hint:

In Newton’s rings experiment, the refractive index is inversely proportional to the square of the ring diameters.

Answer 1

The Correct Option is B

In Newton’s rings experiment, the diameter of the nth dark ring is given by: \[ D_n^2 \propto \frac{\lambda}{n} \] Since the diameters of the rings are in ratio 10:7, the ratio of refractive indices is: \[ \left( \frac{D_1}{D_2} \right)^2 = \frac{n_2}{n_1} \] \[ \left( \frac{10}{7} \right)^2 = \frac{n_2}{n_1} \] \[ \frac{n_2}{n_1} = \frac{100}{49} \] Thus, the correct answer is: \[ Option 2: 49:100. \]