Total Internal Reflection and its Applications NEET Questions

Physics - Optics

Total Internal Reflection and its Applications MCQ Questions


13.
If the critical angle is 45° for a medium, its refractive index is:
A.
2
B.
1/√2
C.
√2 ≈ 1.414
D.
1.5
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ANSWER :
C. √2 ≈ 1.414
14.
The refractive index of a medium is √3. Its critical angle is:
A.
45°
B.
30°
C.
60°
D.
sin⁻¹(1/√3) ≈ 33.56°
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ANSWER :
D. sin⁻¹(1/√3) ≈ 33.56°
15.
Light travels from glass (n = 1.5) into water (n = 1.33). The critical angle for total internal reflection at this interface is:
A.
sin⁻¹(1/1.5) ≈ 41.8°
B.
sin⁻¹(1.33/1.5) ≈ 62.5°
C.
sin⁻¹(1.5/1.33) — invalid (> 1)
D.
sin⁻¹(1/1.33) ≈ 48.75°
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ANSWER :
B. sin⁻¹(1.33/1.5) ≈ 62.5°
16.
Two media have refractive indices 1.4 and 1.6. The critical angle at their interface is:
A.
sin⁻¹(1/1.4) ≈ 45.6°
B.
sin⁻¹(1/1.6) ≈ 38.7°
C.
sin⁻¹(8/7) — invalid
D.
sin⁻¹(7/8) ≈ 61°
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ANSWER :
D. sin⁻¹(7/8) ≈ 61°
17.
The critical angle for a medium depends on:
A.
Only on the temperature alone
B.
Only on the angle of incidence
C.
Only on the polarization of light
D.
The pair of media (refractive indices) and the wavelength of light
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ANSWER :
D. The pair of media (refractive indices) and the wavelength of light
18.
If the wavelength of light is increased, the critical angle for a glass-air interface:
A.
Remains the same
B.
Becomes 90°
C.
Increases (because n decreases for longer wavelengths)
D.
Decreases
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ANSWER :
C. Increases (because n decreases for longer wavelengths)