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A light ray falls on a rectangular glass slab as shown. The index of refraction of the glass, if total internal reflection is to occur at the vertical face, is
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- √3 / 2
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(√3 + 1) 2
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(√2 + 1) 2 - √5 / 2
Correct Option: A
| For point A , aμg = | ||
| sin r |
| ⇒ sin r = | ||
| √2 aμg |
For point B, sin (90° – r) = gµa where, (90° – r) is critical angle.
| ∴ cos r = gμa = | ⇒ aμg = | |||
| aμg | cos r |
| = | = | |||
| √1 - sin² r | √{1 - (1 / 2 aμg2) |
| ⇒ aμg2 = | = | |||||
| 1 - | 2 aμg2 - 1 | |||||
| 2 aμg2 | ||||||
| ⇒ 2 aμg2 - 1 = 2 ⇒ aμg = |  | |
| 2 |
