Ray optics

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Ray Optics

The wave model of light has one serious drawback, though: Unlike other wave phenomena such as sound, or surface waves, it wasn‟t clear what the medium was that supported light waves. Giving it a name – the “luminiferous aether” – didn‟t help. James Clerk Maxwell‟s (1831 – 1879) theory of electromagnetism, however, showed that light was a wave in combined electric and magnetic fields, which, being force fields, didn‟t need a material medium.

Light waves are electromagnetic waves, whose nature is transverse. The speed of light in vacuum is 3 x 10 m/s but it is different in different media.

The speed and wavelength of light change when it travels from one medium to another but its frequency remains unchanged.

Light is electromagnetic radiation that has properties of waves. The electromagnetic spectrum can be divided into several bands based on the wavelength. As we have discussed before, visible light represents a narrow group of wavelengths between about 380 nm and 730 nm.

Our eyes interpret these wavelengths as different colors. If only a single wavelength or limited range of wavelengths are present and enter our eyes, they are interpreted as a certain color. If a single wavelength is present we say that we have monochromatic light. If all wavelengths of visible light are present, our eyes interpret this as white light. If no wavelengths in the visible range are present, we interpret this as dark.

We have further sub-divided the topic into following Topics:-

Reflection and Refraction

 Specular and diffuse reflection

 Refraction and Snell’s law

 Snell’s law

 Total internal reflection

 Dispersion

Mirrors

 Virtual image

 Parabolic mirrors and real images

Lenses

 Convex lenses

 Concave lenses

 Object image height and distance relationship

 Thin lens equation

 Multiple lens systems

 Diopters, Aberration, and the Human Eye

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