Question

define critical angle and obtain expression for it​

Answer 1

Explanation:

Explanation:Critical Angle can be described as the angle of incidence that offers an angle of refraction of 90 degrees. Remember that the critical angle is defined as an angle of incidence value. The critical angle will be 48.6 degrees for water-air boundaries and 61.0 degrees for crown glass-water boundary.

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Answer 2

Answer:

Critical Angle: The critical angle is the angle of incidence, for which the angle of refraction is 90°.  If light enters a denser medium from a comparatively rarer medium, then the direction of light changes and the light ray bends towards the normal.

Formula:

θ$_{cric}$ = $sin^{-1}$ $\frac{nr}{ni}$

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