In a Young's double-slit experiment, the slits are separated by 0.28 mm and the screen is placed 1.4 m away. The distance between the central bright fringe and the fourth bright fringe is measured to be 1.2 m. Determine the wavelength of light used in the experiment.

Solution

Given,
Distance between the screen and slits, D = 1.4 m, Distance between slits, d = 0.28 mm = $0.28 \times 10^{- 3} m$

Fringe width, $ω = \frac{1.2}{4} = 0.3 \times 10^{- 2} m (as the distance 1.2 m is of fourth fringe from central maxima)$

Using formula, we have

Fringe width, $ω = \frac{Dλ}{d}$
$λ = \frac{ωd}{D} = \frac{0.3 \times 10^{- 2} \times 0.28 \times 10^{- 3}}{1.4} = 0.06 \times 10^{- 5} = 600 \times 10^{- 9} = 600 nm .$

which is the required wavelength.

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Wave Optics

In a Young's double-slit experiment, the slits are separated by 0.28 mm and the screen is placed 1.4 m away. The distance between the central bright fringe and the fourth bright fringe is measured to be 1.2 m. Determine the wavelength of light used in the experiment.

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For Daily Free Study Material Join wiredfaculty

Wave Optics

In a Young's double-slit experiment, the slits are separated by 0.28 mm and the screen is placed 1.4 m away. The distance between the central bright fringe and the fourth bright fringe is measured to be 1.2 m. Determine the wavelength of light used in the experiment.

Some More Questions From Wave Optics Chapter

What is the shape of the wavefront in each of the following cases: Light diverging from a point source.

What is the shape of the wavefront in each of the following cases: Light emerging out of a convex lens when a point source is placed at its focus.

What is the shape of the wavefront in each of the following cases:The portion of the wavefront of light from a distant star intercepted by the Earth.

Is the speed of light in glass independent of the colour of light? If not, which of the two colours red and violet travels slower in a glass prism?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

What is the shape of the wavefront in each of the following cases:
Light diverging from a point source.

What is the shape of the wavefront in each of the following cases:
Light emerging out of a convex lens when a point source is placed at its focus.

What is the shape of the wavefront in each of the following cases:
The portion of the wavefront of light from a distant star intercepted by the Earth.