interference fringes were produced using white light in a

Interference fringes were produced using white light in a double slit arrangement. When a mica sheet of uniform thickness of refractive index 1.6 (relative to air) is placed in the path of light from one of the slits, the central fringe moves through some a distance. This distance is equal to the width of 30 interference bands if light of wavelength $$4800\,\mathop {\text{A}}\limits^ \circ $$ is used. The thickness (in $$\mu m$$ ) of mica is

A. 90

B. 12

C. 14

D. 24

Answer : 24

Solution :
Shift of fringe pattern $$ = \left( {\mu - 1} \right)\frac{{tD}}{d}$$
$$\eqalign{ & \therefore \frac{{30D\left( {4800 \times {{10}^{ - 10}}} \right)}}{d} = \left( {0.6} \right)t\frac{D}{d} \cr & 30 \times 4800 \times {10^{ - 10}} = 0.6\,t \cr & t = \frac{{30 \times 4800 \times {{10}^{ - 10}}}}{{0.6}} = \frac{{1.44 \times {{10}^{ - 5}}}}{{0.6}} = 24 \times {10^{ - 6}} \cr} $$

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Releted Question 1

In Young’s double-slit experiment, the separation between the slits is halved and the distance between the slits and the screen is doubled. The fringe width is

A. unchanged.

B. halved

C. doubled

D. quadrupled

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Releted Question 2

Two coherent monochromatic light beams of intensities $$I$$ and $$4\,I$$ are superposed. The maximum and minimum possible intensities in the resulting beam are

A. $$5\,I$$ and $$I$$

B. $$5\,I$$ and $$3\,I$$

C. $$9\,I$$ and $$I$$

D. $$9\,I$$ and $$3\,I$$

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Releted Question 3

A beam of light of wave length $$600\,nm$$ from a distance source falls on a single slit $$1mm$$ wide and a resulting diffraction pattern is observed on a screen $$2\,m$$ away. The distance between the first dark fringes on either side of central bright fringe is

A. $$1.2\,cm$$

B. $$1.2\,mm$$

C. $$2.4\,cm$$

D. $$2.4\,mm$$

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Releted Question 4

Consider Fraunh offer diffraction pattern obtained with a single slit illuminated at normal incidence. At the angular position of the first diffraction minimum the phase difference (in radians) between the wavelets from the opposite edges of the slit is

A. $$\frac{\pi }{4}$$

B. $$\frac{\pi }{2}$$

C. $$2\,\pi $$

D. $$\pi $$

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Releted MCQ Question on
Optics and Wave >> Wave Optics

In Young’s double-slit experiment, the separation between the slits is halved and the distance between the slits and the screen is doubled. The fringe width is

Two coherent monochromatic light beams of intensities $$I$$ and $$4\,I$$ are superposed. The maximum and minimum possible intensities in the resulting beam are

A beam of light of wave length $$600\,nm$$ from a distance source falls on a single slit $$1mm$$ wide and a resulting diffraction pattern is observed on a screen $$2\,m$$ away. The distance between the first dark fringes on either side of central bright fringe is

Consider Fraunh offer diffraction pattern obtained with a single slit illuminated at normal incidence. At the angular position of the first diffraction minimum the phase difference (in radians) between the wavelets from the opposite edges of the slit is

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In Young’s double-slit experiment, the separation between the slits is halved and the distance between the slits and the screen is doubled. The fringe width is

Two coherent monochromatic light beams of intensities $$I$$ and $$4\,I$$ are superposed. The maximum and minimum possible intensities in the resulting beam are

A beam of light of wave length $$600\,nm$$ from a distance source falls on a single slit $$1mm$$ wide and a resulting diffraction pattern is observed on a screen $$2\,m$$ away. The distance between the first dark fringes on either side of central bright fringe is

Consider Fraunh offer diffraction pattern obtained with a single slit illuminated at normal incidence. At the angular position of the first diffraction minimum the phase difference (in radians) between the wavelets from the opposite edges of the slit is

Practice More Releted MCQ Question on Wave Optics

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