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प्रश्न
What is meant by the term ‘critical angle’?
What is a critical angle?
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उत्तर
It is the angle of incidence in the denser medium corresponding to which the angle of refraction in the rarer medium is 90°.
संबंधित प्रश्न
Total internal reflection occurs only when a ray of light passes from a ______ medium to a ______ medium.
Plot a graph between
Sine of angle of incidence versus sine of angle of refraction,
Plot a graph between
Angle of incidence versus angle of refraction.
Make the correct choices for each of the following :
Total Internal reflection takes place when
(where ∠i = angle of incidence, ∠r = angle of refraction, ∠C = critical angle)
How does a ray of light bend when it travels from rarer to denser medium
Write down the relationship between the critical angle and the refractive index of the medium.
How are critical angles related to the refractive index of the medium?
State one factor on which a critical angle for a given pair of media depends. The critical angle for the glass-air interface is 45° for the yellow light. Will it be equal to, less than or greater than 45° for (i) red light, (ii) blue light?
Choose the correct option.
Angles of deviation for extreme colours are given for different prisms. Select the one having maximum dispersive power of its material.
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?
Observe the given figure and write appropriate phenomenon of light in the box.
Optical Fibres are based on the phenomenon of dispersion.
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.
A ray of light passes through a prism of refractive index `sqrt2` as shown in the figure. Find:
- The angle of incidence (∠r2) at face AC.
- The angle of minimum deviation for this prism.
A given ray of light suffers minimum deviation in an equilateral prism P. Additional prism Q and R of identical shape and of the same material as P are now added as shown in the figure. The ray will now suffer ______.
Find the value of θ in the given figure.
The diagram below shows a fish in the tank and its image seen on the surface of the water.
Name the phenomenon responsible for the formation of this image.
State two differences between normal reflection and total internal reflection.
