GK
PHYSICS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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refracted at 90
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reflected at 90
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at maximum diffraction.
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totally absorbed.
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Detailed explanation-1: -This particular angle of incidence is called the critical angle. Here the angle of refraction is 90 degrees. When the angle of incidence is greater than the critical angle, the incident ray is reflected back to the medium. We call this phenomenon total internal reflection.
Detailed explanation-2: -Answer: larger than the critical angle. As mentioned above, the critical angle for the water-air boundary is 48.6 degrees. So for angles of incidence greater than 48.6-degrees, TIR occurs. But 48.6 degrees is the critical angle only for the water-air boundary.
Detailed explanation-3: -The critical angle is the angle of incidence where the angle of refraction is 90°. The light must travel from an optically more dense medium to an optically less dense medium. Figure 5.15: When the angle of incidence is equal to the critical angle, the angle of refraction is equal to 90°.
Detailed explanation-4: -The critical angle (c) is the angle of incidence for which the angle of refraction is 90°. Beyond the critical angle, 100% of the incident light is reflected back into the same medium.
Detailed explanation-5: -The angle of incidence of a ray for which the angle of refraction is 90∘ is called critical angle.