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RAY OPTICS AND OPTICAL INSTRUMENTS — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsRAY OPTICS AND OPTICAL INSTRUMENTS2 Marks
Question
Briefly explain about light.
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Answer

→The human eye is only sensitive to small range of electromagnetic spectrum.
→This region is known as visible light.
→The wavelength of this region is 400 nm to 750 nm.
→Two important points about light:
(i) Light travels with enormous speed. Speed of light is limited and measurable.
→Its presently accepted value in Vacuum is c = 2.99792458 × 108 m/s
→For ease of calculations the velocity of light in free space is taken as c = 3 x 108 m/s
(ii) Light travels in a straight line.

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