221.

The maximum number of possible interference maxima for slit separation equal to twice the wavelength in Young's double-slit experiment, is

• infinite

• five

• three

• zero

A fish, looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is 4/3 and the fish is 12cm below the surface of water, the radius of the circle in centimeter is

• $\frac{12 \times 3}{\sqrt{5}}$

• 12 × 3 × $\sqrt{5}$

• $\frac{12 \times 3}{\sqrt{7}}$

• 12 × 3 × $\sqrt{7}$

In a single slit diffraction experiment, first minimum for λ₁  = 660 nm coincides with first maxima for wavelength λ₂  is

• 950 nm

• 610 nm

• 390 nm

• 440 nm

Two cars A and B approach a stationary observer from opposite sides as shown in the figure hears no beats. If the frequency of the horn of the car B is 504 Hz, the  frequency of horn of the car A will be

• 529.2 Hz

• 295.2 Hz

• 440.5 Hz

• 259.2 Hz

A lens of focal length 1 m forms Fraunhofer diffraction pattern of a single slit of width 0.04 cm in its focal plane. The incident light contains two wavelengths λ₁ and λ₂ . It is found that the fourth minimum corresponding to λ₁ and fifth minimum corresponding to λ₂ occur at the same point 0.5 cm from central maximum, then λ₁ and λ₂ are

• 400 nm, 500 nm

• 500 nm, 700 nm

• 700 nm, 500 nm

• 500 nm, 400 nm

Two coherent light beams of intensity I and 4I are  superposed. The maximum and minimum possible intensities in the resulting beam are

• 5 I and I

• 5 I and 3 I

• 9 I and I

• 9 I and 3 I

If Young's double slit experiment is performed in water instead of air, then

• no fringes would be seen

• fringe width would decrease

• fringe width would increase

• fringe width would remain unchanged

In Young's double-slit experiment, the angular width of fringe formed on a distance screen is 0.1°. If wavelength of light is 6000 $\stackrel{\circ }{\mathrm{A}}$, then spacing between the slits is

• 3.4 × 10^-4 m

• 4.3 × 10^-4 m

• 5.4 × 10^-4 m

• 6.3 × 10^-4 m

A fish at a depth of 12 cm in water is viewed by an observer on the bank of a lake. To what height the image of the fish is raised ?

• 9 cm

• 12 cm

• 3.8 cm

• 3 cm

A ray of light is incident at 50° on the middle of one of the two mirrors arranged at an angle of 60° between them. The ray then touches the second mirror, gets reflected back to the first mirror, making an angle of incidence

• 50°

• 60°

• 70°

• 80°