Wave Optics

Two polarisers P1 and P2 are placed in such a way that the intensity of the transmitted light will be zero. A third polariser P3 is inserted in between P1 and P2, at particular angle between P2 and P3. The transmitted intensity of the light passing through all three polarisers is maximum. The angle between the polarisers P2 and P3 is :

1. /6
2. 3
3. 4
4. /8

In a Young's double slit experiment, two slits are located 1.5 mm apart. The distance of screen from slits is 2 m and the wavelength of the source is 400 nm. If the 20 maxima of the double slit pattern are contained within the central maximum of the single slit diffraction pattern, then the width of each slit is x 10-3 cm, where x-value is .

Two coherent monochromatic light beams of intensities 4I and 9I are superimposed. The difference between the maximum and minimum intensities in the resulting interference pattern is xI. The value of x is .

Two monochromatic light beams have intensities in the ratio 1:9. An interference pattern is obtained by these beams. The ratio of the intensities of maximum to minimum is

1. 8 : 1
2. 4 : 1
3. 3 : 1
4. 9 : 1

Width of one of the two slits in a Young's double slit interference experiment is half of the other slit. The ratio of the maximum to the minimum intensity in the interference pattern is:

1. 3 : 1
2. (2 2 + 1) : (2 2 - 1)
3. 9 : 1
4. (3 + 2 2) : (3 - 2 2)

A light wave is propagating with plane wave fronts of the type x + y + z = constant. The angle made by the direction of wave propagation with the x-axis is :

1. -1(2/3)
2. -1 ( 1 3 )
3. -1 ( 13 )
4. -1 ( 23 )

If the measured angular separation between the second minimum to the left of the central maximum and the third minimum to the right of the central maximum is 30 in a single slit diffraction pattern recorded using 628 nm light, then the width of the slit is .

A double slit interference experiment performed with a light of wavelength 600 nm forms an interference fringe pattern on a screen with 10th bright fringe having its centre at a distance of 10 mm from the central maximum. Distance of the centre of the same 10th bright fringe from the central maximum when the source of light is replaced by another source of wavelength 660 nm would be mm.

A thin transparent film with refractive index 1.4, is held on circular ring of radius 1.8 cm. The fluid in the film evaporates such that transmission through the film at wavelength 560 nm goes to a minimum every 12 seconds. Assuming that the film is flat on its two sides, the rate of evaporation is 10-13 m3/s.

The Young's double slit interference experiment is performed using light consisting of 480 nm and 600 nm wavelengths to form interference patterns. The least number of the bright fringes of 480 nm light that are required for the first coincidence with the bright fringes formed by 600 nm light is

1. 8
2. 4
3. 5
4. 6