# Young’s Double Slit Experiment Questions

Quiz Questions on Young’s Double Slit Experiment:

In which of the following is the interference due to the division of wave front
(a) Young’s double slit experiment
(b) Fresnel’s biprism experiment
(c) Lloyd’s mirror experiment
(d) Demonstration colours of thin film

Ans. (b)

In Young’s double slit experiment the amplitudes of two sources are 3a and a respectively. The ratio of intensities of bright and dark fringes will be
(a) 3 : 1
(b) 4 : 1
(c) 2 : 1
(d)  9 : 1

Ans. (b)

If Fresnel’s biprism experiment as held in water inspite of air, then what will be the effect on fringe width
(a) Decrease
(b) Increase
(c) No effect
(d) None of these

Ans. (a)

In a Young’s double-slit experiment the fringe width is 0.2 mm. If the wavelength of light used is increased by 10% and the separation between the slits is also increased by 10%, the fringe width will be
(a) 0.20 mm
(b) 0.401 mm
(c) 0.242 mm
(d)  0.165 mm

Ans. (a)

Two coherent sources of intensity ratio 1 : 4 produce an interference pattern. The fringe visibility will be
(a) 1
(b) 0.8
(c) 0.4
(d) 0.6

Ans. (b)

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In Young’s double slit experiment, the intensity of light coming from the first slit is double the intensity from the second slit. The ratio of the maximum intensity to the minimum intensity on the interference fringe pattern observed is
(a) 34
(b) 40
(c) 25
(d) 38

Ans. (a)

If the sodium light in Young’s double slit experiment is replaced by red light, the fringe width will
(a) Decrease
(b) Increase
(c) Remain unaffected
(d) First increase, then decrease

Ans. (b)

In an interference experiment, third bright fringe is obtained at a point on the screen with a light of 700 nm. What should be the wavelength of the light source in order to obtain 5th bright fringe at the same point
(a) 500 nm
(b) 630 nm
(c) 750 nm
(d) 420 nm

Ans. (d)

In a Young’s double slit experiment, the source illuminating the slits is changed from blue to violet. The width of the fringes
(a) Increases
(b) Decreases
(c) Becomes unequal
(d) Remains constant

Ans. (b)

In Young’s double slit experiment, the wavelength of the light used is doubled and distance between two slits is half of initial distance, the resultant fringe width becomes
(a) 2 times
(b) 3 times
(c) 4 times
(d) 1/2 times

Ans. (c)

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In Young’s double slit experiment, the distance between the two slits is made half, then the fringe width will become
(a) Half
(b) Double
(c) One fourth
(d) Unchanged

Ans. (b)

In a Young’s double slit experiment, 12 fringes are observed to be formed in a certain segment of the screen when light of wavelength 600 nm is used. If the wavelength of light is changed to 400 nm, number of fringes observed in the same segment of the screen is given by
(a) 12
(b) 18
(c) 24
(d) 30

Ans. (b)

An interference pattern was made by using red light. If the red light changes with blue light, the fringes will become
(a) Wider
(b) Narrower
(c) Fainter
(d) Brighter

Ans. (b)

If a white light is used in Young’s double slit experiments then a very large number of coloured fringes can be seen
(a) With first order violet fringes being closer to the central white fringes
(b) First order red fringes being closer to the central white fringes
(c) With a central white fringe
(d) With a central black fringe

Ans. (c)

Young’s double slit experiment is performed with light of wavelength 550 nm. The separation between the slits is 1.10 mm and screen is placed at distance of 1 m. What is the distance between the consecutive bright or dark fringes
(a) 1.5 mm
(b) 1.0 mm
(c) 0.5 mm
(d) None of these

Ans. (c)

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In the Young’s double slit experiment, for which colour the fringe width is least
(a) Red
(b) Green
(c) Blue
(d) Yellow

Ans. (c)

Two parallel slits 0.6 mm apart are illuminated by light source of wavelength 6000 Å. The distance between two consecutive dark fringes on a screen 1 m away from the slits is
(a) 1 mm
(b) 0.01 mm
(c) 0.1 m
(d) 10 m

Ans. (a)

If a torch is used in place of monochromatic light in Young’s experiment what will happens
(a) Fringe will appear for a moment then it will disappear (b) Fringes will occur as from monochromatic light
(c) Only bright fringes will appear
(d) No fringes will appear

Ans. (d)

In Young’s double slit experiment, the distance between the two slits is 0.1 mm and the wavelength of light used is 4 x 10–7 m. If the width of the fringe on the screen is 4 mm, the distance between screen and slit is
(a) 0.1 mm
(b) 1 cm
(c) 0.1 cm
(d) 1 m

Ans. (d)

In Young’s experiment, one slit is covered with a blue filter and the other (slit) with a yellow filter. Then the interference pattern
(a) Will be blue
(b) Will be yellow
(c) Will be green
(d) Will not be formed

Ans. (d)

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In Young’s double slit experiment, if the widths of the slits are in the ratio 4 : 9, the ratio of the intensity at maxima to the intensity at minima will be
(a) 169 : 25
(b) 81 : 16
(c) 25 : 1
(d) 9 : 4

Ans. (c)

In double slits experiment, for light of which colour the fringe width will be minimum
(a) Violet
(b) Red
(c) Green
(d) Yellow

Ans. (a)

Young’s experiment is performed in air and then performed in water, the fringe width
(a) Will remain same
(b) Will decrease
(c) Will increase
(d) Will be infinite

Ans. (b)

In Young’s experiment, the distance between the slits is reduced to half and the distance between the slit and screen is doubled, then the fringe width
(a) Will not change
(b) Will become half
(c) Will be doubled
(d) Will become four times

Ans. (d)

In a Young’s double slit experiment, the fringe width is found to be 0.4 mm. If the whole apparatus is immersed in water of refractive index 4/3 without disturbing the geometrical arrangement, the new fringe width will be
(a) 0.30 mm
(b) 0.40 mm
(c) 0.53 mm
(d) 450 micron

Ans. (a)

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In Young’s double slit experiment, a glass plate is placed before a slit which absorbs half the intensity of light. Under this case
(a) The brightness of fringes decreases
(b) The fringe width decreases
(c) No fringes will be observed
(d) The bright fringes become fainter and the dark fringes have finite light intensity

Ans. (d)

In a certain double slit experimental arrangement interference fringes of width 1.0 mm each are observed when light of wavelength 5000 Å is used. Keeping the set up unaltered, if the source is replaced by another source of wavelength 6000 Å, the fringe width will be
(a) 0.5 mm
(b) 1.0 mm
(c) 1.2 mm
(d) 1.5 mm

Ans. (c)