Q. 19
A Young’s double slit apparatus has slits separated by 0.28 mm and a screen 48 cm away from the slits. The whole apparatus is immersed in water and the slits are illuminated by the red light (λ = 700 nm in vacuum). Find the fringe-width of the pattern formed on the screen.
Answer :
Given, separation between the slits
The distance between the screen and the slit,
Wavelength of light,
refractive index of water,
Now, the fringe width is given by
But as the light is passing through water, its wavelength changes.
Therefore,
Rate this question :






















Consider the arrangement shown in figure (17-E7). By some mechanism, the separation between the slits S3 and S4 can be changed. The intensity is measured at the point P which is at the common perpendicular bisector of S1S2 and S3S4. When , the intensity measured at P is I. Find this intensity when z is equal to
HC Verma - Concepts of Physics Part 1
The line-width of a bright fringe is sometimes defined as the separation between the points on the two sides of the central line where the intensity falls to half the maximum. Find the line-width of a bright fringe in a Young’s double slit experiment in terms of λ. d and D where the symbols have their usual meanings.
HC Verma - Concepts of Physics Part 1A soap film of thickness 0.0011 mm appears dark when seen by the reflected light of wavelength 580 nm. What is the index of refraction of the soap solution, if it is known to be between 1.2 and 1.5?
HC Verma - Concepts of Physics Part 1Consider the arrangement shown in figure (17-E4). The distance D is large compared to the separation d between the slits. (a) Find the minimum value of d so that there is a dark fringe at O. (b) Suppose d has this value. Find the distance x at which the next bright fringe is formed. (e) Find the fringe-width.
HC Verma - Concepts of Physics Part 1
A parallel beam of light of wavelength 560 nm falls on a thin film of oil (refractive index = 1.4). What should be the minimum thickness of the film so that it strongly reflects, the light?
HC Verma - Concepts of Physics Part 1Consider the situation of the previous problem. If the mirror reflects only 64% of the light energy falling on it, what will be the ratio of the maximum to the minimum intensity in the interference pattern observed on the screen?
HC Verma - Concepts of Physics Part 1A long narrow horizontal slit is placed 1 mm above a horizontal plane mirror. The interference between the light coming directly from the slit and that after reflection is seen on a screen 1.0 m away from the slit. Find the fringe-width if the light used has a wavelength of 700 nm.
HC Verma - Concepts of Physics Part 1A parallel beam of monochromatic light is used in a Young’s double slit experiment. The slits are separated by a distance d and the screen is placed parallel to the plane of the slits. Show that if the incident beam makes an angle with the normal to the plane of the slits, there will be a dark fringe at the center P of the pattern.