Waves Test - 17...

Two point source separated by d=5μm emit light of wavelength λ=2μm in phase. A circular wire of radius 20 mum is placed around the source as shown in figure.

Two monochromatic (wavelength = a/5) and coherent sources of electromagnetic waves are placed on the x-axis at the points (2a, 0) and (_a, 0). A detector moves in a circle of radius R(>>2a) whose centre is at the origin. The number of maximas detected during one circular revolution by the detector are

Two coherent narrow slits emitting light of wavelength l in the same phase are placed parallel to each other at a small separation of 3l. The light is collected on a screen S which is placed at a distance D (>> l) from the slits. The smallest distance x such that the P is a maxima.

A beam of light consisting of two wavelengths 6500 Å and 5200 Å is used to obtain interference fringes in Young's double slit experiment. The distance between slits is 2mm and the distance of screen from slits is 120 cm. What is the least distance from central maximum where the bright due to both wavelength coincide ?

In Young's double slit experiment, the two slits act as coherent sources of equal amplitude A and wavelength l. In another experiment with the same setup the two slits are sources of equal amplitude A and wavelength l but are incoherent. The ratio of the average intensity of light at the midpoint of the screen in the first case to that in the second case is

A monochromatic light source of wavelength l is placed at S. Three slits S₁, S₂ and S₃ are equidistant from the source S and the point P on the screen. S₁P _ S₂P = l/6 and S₁P _ S₃P = 2l/3. If I be the intensity at P when only one slit is open, the intensity at P when all the three slits are open is

In the figure shown in YDSE, a parallel beam of light is incident on the slit from a medium of refractive index n₁. The wavelength of light in this medium is l₁. A transparent slab to thickness `t' and refractive index n<sub>3</sub> is put infront of one slit. The medium between the screen and the plane of the slits is n<sub>2</sub>. The phase difference between the light waves reaching point `O' (symmetrical, relative to the slits) is :

In a YDSE experiment if a slab whose refractive index can be varied is placed in front of one of the slits then the variation of resultant intensity at mid-point of screen with `m' will be best represented by (m ³ 1). [Assume slits of equal width and there is no absorption by slab]

In a YDSE with two identical slits, when the upper slits is covered with a thin, perfectly transparent sheet of mica, the intensity at the centre of screen reduces to 75% of the initial value. Second minima is observed to be above this point and third maxima below it. Which of the following can not be a possible value of phase difference caused by the mica sheet.