A concave mirror has a focal length of 20 cm. The distance between the two positions of the object for which the image size is double of the object size is
For real image:
For virtual image:
or u2 = 10 cm
Therefore, distance between two positions of the object are u1 – u2 or 30cm – 10cm = 20cm.
A ray of light passes from glass, having a refractive index of 1.6, to air. The angle of incidence for which the angle of refraction is twice the angle of incidence is
Consider an equiconvex lens of radius of curvature R and focal length f. Iff > R, the refractive index μ of the material of the lens
A fish is vertically below a flying bird moving vertically down toward water surface. The bird will appear to the fish to be
What is the angle of incidence for an equilateral prism of refractive index so that the ray is parallel to the base inside the prism?
A cube of side 2m is placed in front of a convex mirror of focal length 1 m with its face A at a distance of 3 m and face B at a distance of 5m form the mirror. The distance between the images of faces A and B and heights of images of A and B are, respectively,
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A lens forms a real image of an object. The distance from the object to the lens is x cm and that from the lens to the image is y cm. The graph (see fig) shows the variation of y with x.
It can be deduced that the lens is
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