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प्रश्न
Define a wavefront. Using 'Huygens' principle, draw the shape of a refracted wavefront, when a plane wave is incident on a convex lens.
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उत्तर
The locus of points, which oscillate in phase is called a wavefront; thus a wavefront is defined as a surface of constant phase.
In the given figure we consider a plane wave incident on a thin convex lens, the emerging wavefront is spherical and converges to point F which is known as the focus.
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संबंधित प्रश्न
You have learnt in the text how Huygens’ principle leads to the laws of reflection and refraction. Use the same principle to deduce directly that a point object placed in front of a plane mirror produces a virtual image whose distance from the mirror is equal to the object distance from the mirror.
Consider a plane wave front incident on a thin convex lens. Draw a proper diagram to show how the incident wave front traverses through the lens and after refraction focusses on the focal point of the lens, giving the shape of the emergent wave front.
Using this principle draw a diagram to show how a plane wave front incident at the interface of the two media gets refracted when it propagates from a rarer to a denser medium. Hence verify Snell's law of refraction.
State Huygens’s principle. Show, with the help of a suitable diagram, how this principle is used to obtain the diffraction pattern by a single slit.
Draw a plot of intensity distribution and explain clearly why the secondary maxima becomes weaker with increasing order (n) of the secondary maxima.
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
Relation between ray and wavefront is ______.
What is the geometrical shape of the wavefront for:
- Light diverging from a point source?
- The pattern of wavefront of the light from a distant star intercepted by earth?
Huygen's conception of secondary waves ______.
For light diverging from a point source ______.
- the wavefront is spherical.
- the intensity decreases in proportion to the distance squared.
- the wavefront is parabolic.
- the intensity at the wavefront does not depend on the distance.
What is the shape of the wavefront on earth for sunlight?
