HARD
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An achromatic lens is made using a convex and a concave lens. The power of the achromatic convergent lens of two lenses is +2 D. The power of convex lens is +5 D. The ratio of dispersive power of convex and concave lenses will be

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Important Questions on Ray Optics

MEDIUM
Which is the following colourful patterns is due to diffraction of light?
EASY
Which of the following colour suffers maximum deviation in a prism?
EASY
The separation of a beam of light into its constituent wavelengths is called
HARD
Monochromatic light is incident on a glass prism of angle A. If the refractive index of the material of the prism is μ , a ray, incident at an angle θ , on the face AB would get transmitted through the face AC of the prism provided:

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EASY
A ray is incident at an angle of incidence i on one surface of a small angle prism (with angle of prism A) and emerges normally from the opposite surface. If the refractive index of the material of the prism is μ, then the angle of incidence is nearly equal to:
EASY
If the refracting angle of a prism is 60° and minimum deviation is 30°, then the angle of incidence will be
EASY

In the given figure, what is the angle of prism?

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MEDIUM
What is the required condition, if the light incident on one face of a prism, does not emerge from the other face?
MEDIUM
The focal length of a thin convex lens for red and blue rays are 100 cm and 96.8 cm respectively. Then, the dispersive power of the material of the lens is
EASY
In which colour have maximum dispersion
EASY
The angle of incidence for a ray of light at a refracting surface of a prism is 45o. The angle of prism is 60o. If the ray suffers minimum deviation through the prism, the angle of minimum deviation and refractive index of the material of the prism respectively, are:
MEDIUM
The angle of a prism is 60o . When light is incident at an angle of 60o on the prism, the angle of emergence is 40o . The angle of incidence i for which the light ray will deviate the least is such that
EASY
A parallel beam of light is incident from air at an angle α on the side PQ of a right angled triangular prism of refractive index n=2 . Light undergoes total internal reflection in the prism at the face PR when α has a minimum value of 45o. The angle θ of the prism is:

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EASY
Dispersion without deviation is produced by two thin (small angled) prisms which are combined together. One prism has angle 5° and refractive index 1.56. If the other prism has refractive index 1.7, what is its angle?
EASY
The graph between angle of deviation δ and angle of incidence i for a triangular prism is represented by :
EASY
A ray of light is incident at an angle of 60 on one face of a prism of angle 30 . The emergent ray of light makes an angle of 30 with incident ray. The angle made by the emergent ray with second face of prism will be:
EASY
The refracting angle of a prism is A , and refractive index of the material of the prism is cotA2. The angle of minimum deviation is
EASY
A thin prism P1 with angle 4° and made from glass of refractive index 1.54 is combined with another thin prism P2 made from glass of refractive index 1.72 to produce dispersion without deviation. The angle of prism for P2 is
EASY
A thin prism having refracting angle 10o is made of glass of refractive index 1.42. This prism is combined with another thin prism made of glass of refractive index 1.7. This combination produces dispersion without deviation. The refracting angle of second prism should be
MEDIUM
It was found that the refractive index of material of a certain prism varied as 1.5+0.004λ2, where λ is the wavelength of light used to measure the refractive index. The same material was then used to construct a thin prism of apex angle 10°. Angles of minimum deviation δm of the prism were recorded for the sources with wavelengths λ1 and λ2 respectively. Then