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प्रश्न
What is meant by the term ‘critical angle’?
What is a critical angle?
What do you understand by the term 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
State the conditions required for total internal reflection of light to take place.
Two isosceles right-angle glass prisms P and Q are placed near each other as shown in Fig. Complete the path of the light ray entering the prism P till it emerges out of the prism Q.
Write the relation between the refractive index and critical angle for a given pair of optical media?
One day Chetan’s mother developed a severe stomach ache all of a sudden. She was rushed to the doctor who suggested for an immediate endoscopy test and gave an estimate of expenditure for the same. Chetan immediately contacted his class teacher and shared the information with her. The class teacher arranged for the money and rushed to the hospital. On realizing that Chetan belonged to a below average income group family, even the doctor offered concession for the test fee. The test was conducted successfully.
Answer the following questions based on the above information:
(a) Which principle in optics is made use of in endoscopy?
(b) Briefly explain the values reflected in the action taken by the teacher.
(c) In what way do you appreciate the response of the doctor on the given situation?
(i) Define critical angle.
(ii) State one important factor which affects the critical angle of a given medium.
State two advantages of using a right-angle prism as a reflector, rather than a plane mirror.
Choose the correct option.
Consider the following phenomena/ applications: P) Mirage, Q) rainbow, R) Optical fibre and S) glittering of a diamond. Total internal reflection is involved in
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.
Which of the following is not involved in formation of a rainbow?
Explain ‘mirage’ as an illustration of refraction.
Describe the construction and working of an optical fibre.
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?
Solve Numerical example.
From the given data set, determine angular dispersion by the prism and dispersive power of its material for extreme colours. nR = 1.62 nV = 1.66, δR = 3.1°
For a ray of light, the critical angle is minimum when it travels from ______.
A particle is projected such that the horizontal range and vertical height are equal. Then the angle of projection is :
Optical Fibres are based on the phenomenon of dispersion.
Write any two uses of total internal reflection.
Find the value of θ in the given figure.
