Wave Optics

The wavelength of the light used in Young's double slit experiment is λ. The intensity at a point on the screen is I, where the path difference is $\frac{\mathrm{\lambda }}{6}$. IF I₀ denotes the maximum intensity, then the ratio of I and I₀ is

• 0.866

• 0.5

• 0.707

• 0.75

What is the minimum thickness of a thin film required for constructive interference in the reflected light from it ?Given, the refractive index of the film = 1.5, wavelength of the light incident on the film = 600 nm.

• 100 nm

• 300 nm

• 50 nm

• 200 nm

Critical angle for certain medium is sin^-1 (0.6). The polarizing angle of that medium is

• tan^-1 (1.5)

• sin^-1 (0.8)

• tan^-1 (1.6667)

• tan^-1 (0.6667)

Two monochromatic light waves of amplitudes 3A and 2A interfering at a point have a phase difference of 60°. The intensity at that point will be proportional to

• 5 A²

• 13 A²

• 7 A²

• 19 A²

Consider the following statements in case of Young's double slit experiment.

1. A slit S is necessary if we use an ordinary extended source of light.
2. A slit S is not needed if we use an ordinary but well collimated beam of light.
3.  A slit S is not needed if we use a spatially coherent source of light.

Which ofthe above statements are correct ?

• (1), (2) and (3)

• (1) and (2)

• (2) and (3)

• (1) and (3)

A parallel beam of light ofwavelength 6000 $\stackrel{\circ }{\mathrm{A}}$ gets diffracted by a single slit of width 0.3 mm. The angular position of the first minima of diffracted light is

• 2 × 10^-3 rad

• 3 × 10^-3 rad

• 1.8 × 10^-3 rad

• 6 × 10^-3 rad

The critical angle of a certain medium is ${\sin }^{-1} \left(\frac{3}{5}\right)$. The polarizing angle of the medium is

• ${\sin }^{-1} \left(\frac{4}{5}\right)$

• ${\tan }^{-1} \left(\frac{5}{3}\right)$

• ${\tan }^{-1} \left(\frac{3}{4}\right)$

• ${\tan }^{-1} \left(\frac{4}{3}\right)$

A monochromatic beam of light is travelling from medium A of refractive index n₁ to a medium B of refractive index n₂. In the medium A, there are x number of waves in certain distance. In the medium B, there are y number of waves in the same distance. Then, refractive index of medium A with respect to medium B is

• $\frac{\mathrm{x}}{\mathrm{y}}$

• $\frac{\mathrm{y}}{\mathrm{x}}$

• $\sqrt{\frac{\mathrm{x}}{\mathrm{y}}}$

• $\frac{\mathrm{x}}{\mathrm{y} - \mathrm{x}}$

In Young's double slit experiment, fringes of width β are produced on a screen kept at a distance of 1 m from the slit. When the screen is moved away by 5 x 10^-2 m, fringe width changes by 3 x 10^-5 m. The separation between the slits is 1 x 10^-3 m The wavelength of the light used is

• 400 nm

• 500 nm

• 600 nm

• 700 nm

For sustained interference fringes in double slit experiment, essential condition/s is/are

1. sources must be coherent.
2. the intensities of the two sources must be equal.

Here, the correct option/s is/are

• Neither (1) nor (2)

• Both (1) and (2)

• Only (1)

• Only (2)