If the sodium light in Young’s double slit experiment is replaced by red light, the fringe width will

(1) Decrease

(2) Increase

(3) Remain unaffected

(4) First increase, then decrease

Concept Questions :-

Young Double slit experiment
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Difficulty Level:

In Young’s double slit experiment the wavelength of light was changed from 7000 Å to 3500 Å. While doubling the separation between the slits which of the following is not true for this experiment

(1) The width of the fringes changes

(2) The colour of bright fringes changes

(3) The separation between successive bright fringes changes

(4) The separation between successive dark fringes remains unchanged

Concept Questions :-

Young Double slit experiment
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Difficulty Level:

In Young’s double-slit experiment, an interference pattern is obtained on a screen by a light of wavelength 6000 Å, coming from the coherent sources S1 and S2. At certain point P on the screen third dark fringe is formed. Then the path difference S1PS2P in microns is

(1) 0.75

(2) 1.5

(3) 3.0

(4) 4.5

Concept Questions :-

Young Double slit experiment
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Difficulty Level:

In Young’s double-slit experiment the fringe width is β. If entire arrangement is placed in a liquid of refractive index n, the fringe width becomes

(1) $\frac{\beta }{n+1}$

(2)

(3) $\frac{\beta }{n}$

(4) $\frac{\beta }{n-1}$

Concept Questions :-

Young Double slit experiment
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Difficulty Level:

In Young’s double slit experiment, distance between two sources is 0.1 mm. The distance of screen from the sources is 20 cm. Wavelength of light used is 5460 Å. Then angular position of the first dark fringe is

(1) 0.08°

(2) 0.16°

(3) 0.20°

(4) 0.313°

Concept Questions :-

Young Double slit experiment
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Difficulty Level:

In a Young’s double slit experiment, the slit separation is 0.2 cm, the distance between the screen and slit is 1m. Wavelength of the light used is 5000 Å. The distance between two consecutive dark fringes (in mm) is

(1) 0.25

(2) 0.26

(3) 0.27

(4) 0.28

Concept Questions :-

Young Double slit experiment
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Difficulty Level:

A star emitting light of wavelength 5896 Å is moving away from the earth with a speed of 3600 km/sec. The wavelength of light observed on earth will

(1) Decrease by 5825.25 Å

(2) Increase by 5966.75 Å

(3) Decrease by 70.75 Å

(4) Increase by 70.75 Å

(c = 3 × 108 m/sec is the speed of light)

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A heavenly body is receding away from the earth such that the fractional change in λ is 1, then its velocity is :

(1) C

(2) $\frac{3C}{5}$

(3) $\frac{C}{5}$

(4) $\frac{2C}{5}$

Concept Questions :-

Wave front
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A slit of width a is illuminated by white light. For red light (λ = 6500 Å), the first minima is obtained at θ = 30°. Then the value of a will be

(1) 3250 Å

(2) 6.5 × 10–4 mm

(3) 1.24 microns

(4) 2.6 × 10–4 cm

Concept Questions :-

Diffraction
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Difficulty Level:

The radius of central zone of the circular zone plate is 2.3 mm. The wavelength of incident light is $5893\text{\hspace{0.17em}\hspace{0.17em}}Å.$ Source is at a distance of 6m. Then the distance of the first image will be

(1) 9 m

(2) 12 m

(3) 24 m

(4) 36 m

Concept Questions :-

Huygens' principle