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(d) a concave lens
(a) 90 cm
(a) +10cm
(c) 0 degree
(a) d<20cm
The image of an object formed by an optical device is always virtual and small. The device may be
(d) a concave lens
(d) a concave lens
See lessThe focal length of a concave mirror lens is 18cm and the size of the image is a quarter of the object. The object is situated at a distance of
(a) 90 cm
(a) 90 cm
See lessTwo lenses of power +12D and -2D are placed in contact. The focal length of the combination is
(a) +10cm
(a) +10cm
See lessA ray of light continues to move along the same path while passing through an air-glass interface. The angle of incidence for the light ray is
(c) 0 degree
(c) 0 degree
See lessTo form an erect image twice the size of an object by using a convex lens of focal length 20cm the object should be placed at a distance ‘d’ from the optical centre of lens.Here’d’ is
(a) d<20cm
(a) d<20cm
See less