A level Wave Optics Quiz. In physics, **physical optics**, or **wave optics**, is the branch of optics that studies interference, diffraction, polarization, and other phenomena for which the ray approximation of geometric optics is not valid. This usage tends not to include effects such as quantum noise in optical communication, which is studied in the sub-branch of coherence theory.

*Physical optics* is also the name of an approximation commonly used in optics, electrical engineering and applied physics. In this context, it is an intermediate method between geometric optics, which ignores wave effects, and full wave electromagnetism, which is a precise theory. The word "physical" means that it is more physical than geometric or ray optics and not that it is an exact physical theory. :11–13

This approximation consists of using ray optics to estimate the field on a surface and then integrating that field over the surface to calculate the transmitted or scattered field. This resembles the Born approximation, in that the details of the problem are treated as a perturbation.

In optics, it is a standard way of estimating diffraction effects. In radio, this approximation is used to estimate some effects that resemble optical effects. It models several interference, diffraction and polarization effects but not the dependence of diffraction on polarization. Since this is a high-frequency approximation, it is often more accurate in optics than for radio.

In optics, it typically consists of integrating ray-estimated field over a lens, mirror or aperture to calculate the transmitted or scattered field.

In radar scattering it usually means taking the current that would be found on a tangent plane of similar material as the current at each point on the front, i. e. the geometrically illuminated part, of a scatterer. Current on the shadowed parts is taken as zero. The approximate scattered field is then obtained by an integral over these approximate currents. This is useful for bodies with large smooth convex shapes and for lossy (low-reflection) surfaces.

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Two coherent monochromatic light beams of intensities I and 41 superimpose. The maximum and minimum possible intensities in the resulting beam are:

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When exposed to sunlight, thin films of oil on water of ten exhibit brilliant colours due to the phenomenon of

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What happens, if the monochromatic light used in Young’s double slit experiment is replaced by white light?

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When compact disk is illuminated by a source of white light, coloured lines are observed. This is due to

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When unpolarised light beam is incident from air onto glass (n = 1.5) at the polarising angle.

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A double slit interference experiment is carried out in air and the entire arrangement is dipped in water. The fringe width

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In Young’s double slit experiment, if the monochromatic source of yellow light is replaced by red light, the fringe width

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The angle of incidence at which reflected light is totally polarised for reflection from air to glass (refractive index n) is