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प्रश्न
Name two factors which affect the critical angle for a given pair of media. State how do the factors affect it.
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उत्तर
The factors which affect the critical angle are:
- Wavelength (colour) of light: Since a transparent medium's refractive index increases with violet light and decreases with red light, the critical angle for a pair of media increases with red light and decreases with violet light. Thus, the critical angle rises as the light's wavelength increases.
- The temperature: The critical angle for that pair of media increases as the temperature of the medium rises because its refractive index falls. As a result, the critical angle rises as the temperature rises.
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संबंधित प्रश्न
The figure shows a ray of light falling normally on the face AB of an equilateral glass prism having refractive index`3/2`, placed in water of refractive index `4/3`.Will this ray suffer total internal reflection on striking the face AC? Justify your answer.
(i) Define critical angle.
(ii) State one important factor which affects the critical angle of a given medium.
Write down the relationship between the critical angle and the refractive index of the medium.
Name the factors affecting the critical angle for the pair of media.
Solve Numerical example.
A monochromatic ray of light is incident at 37° on an equilateral prism of refractive index 3/2. Determine angle of emergence and angle of deviation. If angle of prism is adjustable, what should its value be for emergent rays to be just possible for the same angle of incidence?
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A rectangular block of glass ABCD has a refractive index 1.6. A pin is placed midway on the face AB (Figure). When observed from the face AD, the pin shall ______.
- appear to be near A.
- appear to be near D.
- appear to be at the centre of AD.
- not be seen at all.
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Name the phenomenon responsible for the formation of this image.
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