Wave Optics

In Young's double slit experiment, the slits are 2 mm apart and are illuminated by photons of two wavelengths 1 = 12000 A and 2 = 10000 A. At what minimum distance from the common central bright fringe on the screen 2 m from the slit will a bright fringe from one interference pattern coincide with a bright fringe from the other ?

1. 4 mm
2. 3 m
3. 8 mm
4. 6 mm

In Young's double slit experiment the distance between the slits and the screen is doubled. The separation between the slits is reduced to half. As a result the fringe width

1. is halved
2. becomes four times
3. remains unchanged
4. is doubled

A parallel beam of light of wavelength is incident normally on a narrow slit. A diffraction pattern is formed on a screen placed perpendicular to the direction of the incident beam. At the second minimum of the diffraction pattern, the phase difference between the rays coming from the two edges of slit is

1. 2
2. 3
3. 4

The angular resolution of a 10 cm diameter telescope at a wavelength of 5000 A is of the order of

1. 106 rad
2. 10-2 rad
3. 10-4 rad
4. 10-6 rad.

A telescope has an objective lens of 10 cm diameter and is situated at a distance of one kilometer from two objects. The minimum distance between these two objects, which can be resolved by the telescope, when the mean wavelength of light is 5000 A, is of the order of

1. 0.5 m
2. 5 m
3. 5 mm
4. 5 cm

Diameter of human eye lens is 2 mm. What will be the minimum distance between two points to resolve them, which are situated at a distance of 50 metre from the eye? The wavelength of light is 5000 Å.

1. 2.32 m
2. 4.28 mm
3. 1.25 cm
4. 12.48 cm