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What is the wavelength of a source B If in Young's experiment, the third bright band for a wavelength of light (source A) 6000 Å coincides with the fourth bright band for source B in the same arrangement. 

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Important Questions on Optics

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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
Young's double slit experiment is first performed in air and then in a medium other than air. It is found that 8th bright fringe in the medium lies where 5th dark fringe lies in air. The refractive index of the medium is nearly
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
In a Young's double slit experiment, slits are separated by 0.5 mm, and the screen is placed 150 cm away. A beam of light consisting of two wavelengths, 650 nm and 520 nm, is used to obtain interference fringes on the screen. The least distance from the common central maximum to the point where the bright fringes due to both the wavelengths coincide is:
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
In the Young's double slit experiment using a monochromatic light of wavelength λ , the path difference ( in terms of an integer n ) corresponding to any point having half the peak intensity is
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
In a Young's double slit experiment, the slits are placed 0.320 mm apart. Light of wavelength λ=500 nm is incident on the slits. The total number of bright fringes that are observed in the angular range -30o≤θ≤30o is:
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
Consider a Young's double slit experiment as shown in figure. What should be the slit separation d in terms of wavelength λ such that the first minima occurs directly in front of the slit (S1) ?

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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
In Young’s double-slit experiment, the distance between the two identical slits is 6.1 times larger than the slit width. Then the number of intensity maxima observed within the central maximum of the single-slit diffraction pattern is :
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
In Young's double-slit experiment, in an interference pattern, the second minimum is observed exactly in front of one slit. The distance between the slits is d and the distance between source and screen is D. The wavelength of the light source used is
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
In a double – slit experiment, at a certain point on the screen the path difference between the two interfering waves is 18th of a wavelength. The ratio of the intensity of light at that point to that at the center of a bright fringe is:
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
The distance between two coherent sources is 1 mm. The screen is placed at a distance of 1 m from the sources. If the distance of the third bright fringe is 1.2 mm from the central fringe, the wavelength of light used is
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
The interference pattern is obtained with two coherent light sources of intensity ratio, n. In the interference pattern, the ratio, Imax−IminImax+Imin will be
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
A light source, which emits two wavelengths λ1=400 nm and λ2=600 nm , is used in a Young's double slit experiment. If recorded fringe widths for λ1 and λ2 are β1 and β2 and the number of fringes for them within a distance y on one side of the central maximum are m1 and m2 , respectively, then
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
In Young's double-slit experiment, using monochromatic light of wavelength λ, the intensity of light at a point on the screen where path difference is λ is K units. Then, the intensity of light at a point where path difference is λ3 is
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
In a double slit experiment, when light of wavelength 400 nm was used, the angular width of the first minima formed on a screen placed 1 m away was found to be 0.2°. What will be the angular width of the first minima, if the entire experimental apparatus is immersed in water? μwater=43
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width

Using monochromatic light of wavelength λ , an experimentalist sets up the Young's double slit experiment in three ways as shown.
If she observes that y⁡ = β ′ , the wavelength of light used is :

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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
In a Young's double slit experiment 15 fringes are observed on a small portion of the screen when light of wavelength 500 nm is used. Ten fringes are observed on the same section of the screen when another light source of wavelength λ is used. Find the value of λ (in nm ) .
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
In Young's double slit experiment using monochromatic light of wavelength λ, the intensity of light at a point on the screen where path different is λ is K units. The intensity of light at a point where path difference is λ3 is
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
In a Young’s double slit experiment, the separation between the slits is 0.15 mm . In the experiment, a source of light of wavelength 589 nm is used and the interference pattern is observed on a screen kept 1.5 m away. The separation between the successive bright fringes on the screen is:
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
Electrons accelerated from rest by an electrostatic potential are collimated and sent through a Young's double slit experiment. The fringe width is ω. If the accelerating potential is doubled, then the width is now close to:
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
In a double-slit experiment, the two slits are 1 mm apart and the screen is placed 1 m away. A monochromatic light of wavelength 500 nm is used. What will be the width of each slit for obtaining ten maxima of double-slit within the central maxima of a single-slit pattern?
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Physics>Optics>Optics>Interference - Young’s Double Slit Experiment and Expression for Fringe Width
In a Young's double slit experiment slit separation 0.1 mm, one observes a bright fringe at angle 140 rad by using light of wavelength λ1. When the light of wavelength λ2 is used a bright fringe is seen at the same angle in the same set up. Given that λ1 and λ2 are in visible range 380 nm to 740 nm, their values are: