A wavefront is represented by the plane y = 3-x. The propagation of the wave takes place at

• 45° with x direction

• 135° with x direction

• 60° with x direction

• No sufficient data

The intensity ratio of two coherent sources of light is P. They are interfering in the same region and produce an interference pattern. Then the fringe visibility is

• $\frac{1+\mathrm{P}}{2\sqrt{\mathrm{P}}}$

• $\frac{2\sqrt{\mathrm{P}}}{1+\mathrm{P}}$

• $\frac{\mathrm{P}}{1+\mathrm{P}}$

• $\frac{2\mathrm{P}}{1+\mathrm{P}}$

The wavefront of a wave has direction with wave motion

• parallel

• perpendicular

• opposite

• at an angle of θ

A beam of light of wavelength 600 nm from a distant source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between the first dark fringes on either side of the central bright fringe is

• 1.2 cm

• 1.2 mm

• 2.4 cm

• 2.4 mm

The specific rotation of a sugar solution is 0.5 deg m²/kg. 200 kg-m^-3 of impure sugar solution is- taken in a sample polarimeter tube of length 20 cm and optical rotation is found to be 19°. The percentage of purity of sugar is

• 20%

• 80%

• 95%

• 89%

In Young's double-slit experiment with sodium vapor lamp of wavelength 589 nm and the slits 0.589 min apart, the half angular width of the central maximum is

• sin^-1(0.01)

• sin^-1(0.0001)

• sin^-1(0.001)

• sin^-1(0.1)

When the angle of incidence is 60° on the surface of a glass slab, it is found that the reflected ray is completely polarised. The velocity of light in glass is

• √2 x 10⁸ ms^-1

• √3 x 10⁸ ms^-1

• 2 x 10⁸ ms^-1

• 3 x 10⁸ ms^-1

88.

The intensity of sound gets reduced by 10% on passing through a slab. The reduction in intensity on passing through two consecutive slabs would be

• 20 %

• 19 %

• 5 %

• 50 %

Four independent waves are expressed as

$$\begin{gathered} \left(\mathrm{i}\right) {\mathrm{y}}_1 = {\mathrm{a}}_1\mathrm{sin\omega t} \\ \left(\mathrm{ii}\right) {\mathrm{y}}_2 = {\mathrm{a}}_2\mathrm{sin\omega t} \\ \left(\mathrm{iii}\right) {\mathrm{y}}_3 = {\mathrm{a}}_3\mathrm{cos\omega t} \\ \left(\mathrm{iv}\right) {\mathrm{y}}_4 = {\mathrm{a}}_4\sin \left(\mathrm{\omega t} + \frac{\mathrm{\pi }}{3}\right) \end{gathered}$$

• (i) and (iii)

• (i) and (iv)

• (ii) and (iv)

• not possible at all

Two coherent monochromatic light beams of intensities I and 4 I superimpose. The maximum and minimum possible intensities in the resulting beam are respectively

• 5I and I

• 5I and 3I

• 3I and I

• 9I and I