A. center of curvature
B. focus
C. optical center
D. aperture
0
Dioptre power of an concave lens of 10 cm focal length is_______________?
0
The minimum distance between an object and its real image in a convex lens is_____________?
A. 10 dioptre
B. 10 dioptre
C. 1 / 10 dioptre
D. 1 / 10 dioptre
0
A convex lens gives a virtual image only when the objects lies_________________?
A. 2 f
B. 2.5 f
C. 3f
D. 4f
0
Image of an object 5 mm high is only 1 cm high. Magnification produced by lens is__________________?
A. between principal focus and center of curvature
B. beyond 2 f
C. at the principal focus
D. between principal focus and optical center
0
Least distance of distinct vision_____________?
A. 0.5
B. 0.2
C. 1
D. 2
0
Two convex lenses of equal focal length f are placed in contact the resultant focal length of the combination is______________?
A. increases with increase in age
B. decreases with increase in age
C. neither increases nor decreases
D. becomes infinite after 60 years
0
For normal adjustment, length of astronomical telescope is______________?
A. zero
B. focus
C. 2 f
D. f/2
0
Final image produced by a compound microscope is_____________?
A. fo + fe
B. fo – fe
C. fo / fe
D. fe / fo
0
In multimode step index fibre the refractive index of core and cladding is____________?
A. real and inverted
B. real and erect
C. virtual and erect
D. virtual and inverted
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