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Physics · Textbook solutions

Wave Optics

Every solved example, exercise, and miscellaneous question — in the order the textbook teaches them. · 12 questions

Worked Examples

2 q

Solved Examples

Worked · 2
  1. Eg 10.1
    (a) When monochromatic light is incident on a surface separating two media, the reflected and refracted light both have the same frequency as the incident frequency. Explain why? (b) When light travels from a rarer to a denser medium, the speed decreases. Does the reduction in speed imply a reduction in the energy carried by the light wave? (c) In the wave picture of light, intensity of light is determined by the square of the amplitude of the wave. What determines the intensity of light in the photon picture of light.
  2. Eg 10.2
    Discuss the intensity of transmitted light when a polaroid sheet is rotated between two crossed polaroids?

Exercises

10 q
  1. Ex 10.1
    Monochromatic light of wavelength 589 nm589\,\text{nm} is incident from air on a water surface. What are the wavelength, frequency and speed of (a) reflected, and (b) refracted light? Refractive index of water is 1.331.33.
  2. Ex 10.2(a)
    What is the shape of the wavefront in each of the following cases: (a) Light diverging from a point source.
  3. Ex 10.2(b)
    What is the shape of the wavefront in each of the following cases: (b) Light emerging out of a convex lens when a point source is placed at its focus.
  4. Ex 10.2(c)
    What is the shape of the wavefront in each of the following cases: (c) The portion of the wavefront of light from a distant star intercepted by the Earth.
  5. Ex 10.3(a)
    (a) The refractive index of glass is 1.51.5. What is the speed of light in glass? (Speed of light in vacuum is 3.0×108 m s−13.0 \times 10^{8}\,\text{m s}^{-1})
  6. Ex 10.3(b)
    (b) 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?
  7. Ex 10.4
    In a Young's double-slit experiment, the slits are separated by 0.28 mm0.28\,\text{mm} and the screen is placed 1.4 m1.4\,\text{m} away. The distance between the central bright fringe and the fourth bright fringe is measured to be 1.2 cm1.2\,\text{cm}. Determine the wavelength of light used in the experiment.
  8. Ex 10.5
    In Young's double-slit experiment using monochromatic light of wavelength λ\lambda, the intensity of light at a point on the screen where path difference is λ\lambda, is KK units. What is the intensity of light at a point where path difference is λ/3\lambda/3?
  9. Ex 10.6(a)
    A beam of light consisting of two wavelengths, 650 nm650\,\text{nm} and 520 nm520\,\text{nm}, is used to obtain interference fringes in a Young's double-slit experiment. (a) Find the distance of the third bright fringe on the screen from the central maximum for wavelength 650 nm650\,\text{nm}.
  10. Ex 10.6(b)
    A beam of light consisting of two wavelengths, 650 nm650\,\text{nm} and 520 nm520\,\text{nm}, is used to obtain interference fringes in a Young's double-slit experiment. (b) What is the least distance from the central maximum where the bright fringes due to both the wavelengths coincide?