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A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since:

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Important Questions on Ray Optics

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Find the value of the angle of emergence from the prism. Refractive index of the glass is 3.

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A point object is placed at a distance of 60 cm from a convex lens of focal length 30 cm. If a plane mirror were put perpendicular to the principal axis of the lens and at a distance of 40 cm from it, the final image would be formed at a distance of :

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An object is placed on the principal axis of a concave mirror at a distance of 1.5f (f is the focal length). The image will be at,
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If the critical angle for total internal reflection from a medium to vacuum is 45°, then velocity of light in the medium is,
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The power of a biconvex lens is 10 dioptre and the radius of curvature of each surface is 10 cm. Then the refractive index of the material of the lens is,
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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:
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Pick the wrong answer in the context with rainbow.
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Two similar thin equi-convex lenses of focal length f each are kept coaxially in contact with each other, such that the focal length of the combination is F1. When the space between the two lenses is filled with glycerin (which has the same refractive index (μ=1.5) as that of glass), then the equivalent focal length is F2. The ratio F1:F2 will be