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1. The principal focus of a convex lens is the point where
A. Rays parallel to the axis converge
B. Rays diverge from the axis
C. Rays meet after reflection
D. No deviation occurs
2. The image formed by a concave lens is always
A. Real and inverted
B. Enlarged and real
C. Virtual and erect
D. Same size and real
3. Lens formula is
A. 1/v – 1/u = 1/f
B. 1/v + 1/u = 1/f
C. v/u = f
D. f = u + v
4. The unit of power of a lens is
A. Watt
B. Dioptre
C. Candela
D. Lumen
5. A convex lens of focal length 50 cm has power
A. +2 D
B. +0.5 D
C. +1 D
D. +0.2 D
8. If an object is placed at 2F in front of a convex lens, the image is formed at
A. Infinity
B. Between F and 2F
C. At 2F
D. At focus
9. In a convex lens, when the object is between F and O, the image formed is
A. Real and inverted
B. Virtual and erect
C. Same size and inverted
D. Diminished and real
10. A concave mirror forms a highly enlarged image when the object is placed
A. At infinity
B. At C
C. At focus
D. Between C and F
11. The emergent ray through a rectangular glass slab is
A. Parallel to incident ray
B. Perpendicular to incident ray
C. Bent more
D. Totally deviated
12. The magnification (m) is equal to
A. v/u
B. h’/h
C. –v/u
D. Both B and C
14. Which of these has the highest refractive index?
A. Sapphire
B. Diamond
C. Water
D. Glass
15. A magnifying glass is an example of
A. Concave mirror
B. Convex lens
C. Concave lens
D. Convex mirror
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