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प्रश्न
Use Huygens’s principle to explain the formation of diffraction pattern due to a single slit illuminated by a monochromatic source of light.
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उत्तर
Consider a parallel beam of monochromatic light is incident normally in a slit of width b as shown if figure. According to Huygens’s principle every point of slit acts as a source of secondary wavelets spreading in all directions. Screen is placed at a larger distance.
Consider a particular point P on the screen receives waves from all the secondary sources. All these waves start from different point of the slit and interface at point P to give
Point P0 is at bisector plane of the slit. At P0, all waves are traveling equal optical path. So are in phase the waves thus interface constructively with each other and maximum intensity is observed. As we move from P0, the wave arrives with different phase and intensity is changed. Intensity at point P is given by
`I = I_0 (sin^2α)/alpha`
where `alpha = pi/lambda b sin theta`
For central maxima α = 0 thus,
I = I0
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संबंधित प्रश्न
Using Huygens's construction of secondary wavelets explain how a diffraction pattern is obtained on a screen due to a narrow slit on which a monochromatic beam of light is incident normally.
What is the shape of the wavefront in the following case?
Light emerging out of a convex lens when a point source is placed at its focus.
Using Huygens’ principle, verify the laws of reflection at a plane surface.
When the width of the slit is made double the original width, how would this affect the size and intensity of the central diffraction band?
Huygens' principle of secondary wavelets may be used to
(a) find the velocity of light in vacuum
(b) explain the particle behaviour of light
(c) find the new position of a wavefront
(d) explain Snell's Law
Derive the law of reflection using Huygen’s Wave Theory.
Answer the following question.
Define the term wavefront. Using Huygen's wave theory, verify the law of reflection.
The inverse square law of intensity is valid for a
Figure shows a standard two slit arrangement with slits S1, S2, P1, P2 are the two minima points on either side of P (Figure). At P2 on the screen, there is a hole and behind P2 is a second 2-slit arrangement with slits S3, S4 and a second screen behind them.
Represent diagrammatically how the incident planar wavefronts of wavelength λ pass through an aperture of size d, when d is approximately equal to λ.
