# Topic: Chapter 2: Optics (Test 1)

Topic: Chapter 2: Optics
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• Test: 1(current)
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Q.1
The refractive index of four substances A, B, C and D are 1.31, 1.43, 1.33, 2.4 respectively. The speed of light is maximum in
A. A
B. B
C. C
D. D
Explaination / Solution:
No Explaination.

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Q.2
Where should an object be placed so that a real and inverted image of same size is obtained by a convex lens
A. f
B. 2f
C. infinity
D. between f and 2f
Explaination / Solution:
No Explaination.

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Q.3
A small bulb is placed at the principal focus of a convex lens. When the bulb is switched on, the lens will produce
A. a convergent beam of light
B. a divergent beam of light
C. a parallel beam of light
D. a coloured beam of light
Explaination / Solution:
No Explaination.

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Q.4
Magnification of a convex lens is
A. positive
B. negative
C. either positive or negative
D. zero
Explaination / Solution:
No Explaination.

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Q.5
A convex lens forms a real, diminished point sized image at focus. Then the position of the object is at
A. focus
B. infinity
C. at 2f
D. between f and 2f
Explaination / Solution:
No Explaination.

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Q.6
Power of a lens is –4D, then its focal length is
A. 4m
B. –40m
C. –0.25 m
D. –2.5 m
Explaination / Solution:
No Explaination.

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Q.7
In a myopic eye, the image of the object is formed
A. behind the retina
B. on the retina
C. in front of the retina
D. on the blind spot
Explaination / Solution:
No Explaination.

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Q.8
The eye defect ‘presbyopia’ can be corrected by
A. convex lens
B. concave lens
C. convex mirror
D. Bi focal lenses
Explaination / Solution:
No Explaination.

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Q.9
Which of the following lens would you prefer to use while reading small letters found in a dictionary?
A. A convex lens of focal length 5 cm
B. A concave lens of focal length 5 cm
C. A convex lens of focal length 10 cm
D. A concave lens of focal length 10 cm
Explaination / Solution:
No Explaination.

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Q.10
If VB, VG, VR be the velocity of blue, green and red light respectively in a glass prism, then which of the following statement gives the correct relation?
A. VB = VG = VR
B. VB > VG >VR
C. VB < VG < VR
D. VB < VG > VR