Page 1 - Wave Optics Work Sheet -1

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Work Sheet -1 on Physics

Chapter -10, Class -12

Wave Optics( Huygen’s Wave Theory, Reflection and Refraction)

1. What type of wavefront will emerge from a
(i) point source, and
(ii) distant light source? (Delhi 2008)
2. Draw a diagram to show refraction of a plane wave front incident in a convex lens and
hence draw the refracted wave front. (Delhi 2008)
3. Differentiate between a ray and a wave front. (Delhi 2008)
4. Define the term ‘wavefront’.(Comptt. All India 2013)
5. Draw the shape of the wavefront coming out of a convex lens when a plane wave is
incident on it. (Comptt. All India 2013)
6. Define the term wave front. State Huygen’s principle.
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. (All
India 2015)
7. A plane wavefront is incident at an angle of incidence i on a reflecting surface. Draw a
diagram showing incident wavefront, reflected wavefront and verify the laws of reflection.
(Comptt. Delhi 2015)
8. (a) State Huygen’s principle. 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.
(b) When monochromatic light travels from a rarer to a denser medium, explain the
following, giving reasons :
(i) Is the frequency of reflected and refracted light same as the frequency of incident
light?
(ii) Does the decrease in speed imply a reduction in the energy carried by light wave?
(Delhi 2010)
9. (a) Define a wavefront. How is it different from a ray?
(b) Depict the shape of a wavefront in each of the following cases.
(i) Light diverging from point source.
(ii) Light emerging out of a convex lens when a point source is placed at its focus.
(iii) Using Huygen’s construction of secondary wavelets, draw a diagram showing the
passage of a plane wavefront from a denser into a rarer medium. (Comptt. All India
2014)
10. The wavefront due to a source situated at infinity is
(a) spherical
(b) cylindrical

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