Glass has refractive index 1.5 with respect to air. A light ray inside…

Question

Glass has refractive index 1.5 with respect to air. A light ray inside the glass strikes the glass–air boundary at 45°. The ray will

Accepted Answer

D. {'text': 'undergo total internal reflection', 'label': 'D'}

1. Critical angle from glass to air: sin θc = 1 / 1.5 = 2/3 ≈ 0.667 ⇒ θc ≈ 41.8°.
2. The incidence angle 45° > θc, so refraction cannot occur — the ray totally internally reflects.
3. (D) describes grazing emergence at exactly θc, not above it.
_Source: NCERT Class 12 Physics Part II, Ch 9 §9.4_

Answer

{'text': 'be partially absorbed', 'label': 'A'}

Answer

{'text': 'refract out into air at sin⁻¹(0.75)', 'label': 'B'}

Answer

{'text': 'graze along the interface', 'label': 'C'}