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Free download in PDF Lenses Objective Type Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams like IIT-JEE, JIPMER, NEET, AIIMS etc. These short solved questions or quizzes are provided by Gkseries.
(21)
Dental mirror is what type of a mirror?
[A]
Convex mirror
[B]
Concave mirror
[C]
Plane mirror
[D]
Both (b) and (c)
(22)
Suppose you are standing 1 m in front of a plane mirror. What should be the minimum vertical size of the mirror so that you can see your full image in it?
[A]
0.50 m
[B]
2 m
[C]
half of your height
[D]
twice your height
Answer: half of your height
(23)
A spherical air bubble is embedded in a piece of glass. For a ray of light passing through the bubble, it behaves like a :
[A]
converging lens
[B]
diverging lens
[C]
plano-converging lens
[D]
plano-diverging lens
(24)
What is the power of the lens, if the far point of a short-sighted eye is 200 cm?
[A]
-0.5 D
[B]
2 D
[C]
1 D
[D]
-1.5 D
(25)
The image formed by a convex mirror of a real object is larger than the object
[A]
when u < 2f
[B]
when u > 2f
[C]
for all values of u
[D]
for no value of u
Answer: for no value of u
(26)
The mirror used for the head light of a car is
[A]
spherical concave
[B]
plane
[C]
cylindrical
[D]
parabolic concave
Answer: parabolic concave
(27)
The radius of curvature of a plane mirror
[A]
is zero
[B]
is infinity
[C]
can be anywhere between zero and infinity
[D]
None of the above
(28)
An object is placed at the focus of a concave mirror. The image will be
[A]
real, inverted, same size at the focus
[B]
real, upright, same size at the focus
[C]
virtual, inverted, highly enlarged at infinity
[D]
real, inverted, highly enlarged at infinity
Answer: real, inverted, highly enlarged at infinity
(29)
An optician prescribes a power = - 0.5 dioptre. The corresponding lens must be a
[A]
convex lens of focal length 2 m
[B]
convex lens of focal length 50 cm
[C]
concave lens of focal length 2 m
[D]
concave lens of focal length 50 cm
Answer: concave lens of focal length 2 m
(30)
What kind of image is created by a concave lens?
[A]
upright and smaller
[B]
inverted and smaller
[C]
inverted and larger
[D]
upright and smaller
Answer: upright and smaller
31
What kind of lens is used by short-sighted persons?
[A]
convex
[B]
concave
[C]
cylindrical
[D]
None of the above
32
An object is kept 5 cm in front of a concave mirror of focal length of 15 cm. What will be the nature of the image?
[A]
virtual, not magnified
[B]
virtual, magnified
[C]
real, magnified
[D]
real not magnified
Answer: virtual, magnified
33
What type of mirror is used in a view finding mirror of a vehicle?
[A]
Convex mirror
[B]
Concave mirror
[C]
Plane mirror
[D]
Paraboloidal mirror
34
A number of images of a candle flame can be seen in a thick mirror. The brightest image is -
[A]
last
[B]
fourth
[C]
third
[D]
second
35
An object is placed at a distance of 12 cm from a convex lens on its principal axis and a virtual image of certain size is formed. If the object is moved further 8 cm away from the lens, a real image of the same size as that of the virtual image is formed . Which one of the following is the focal length of the lens?
[A]
15 cm
[B]
16 cm
[C]
18 cm
[D]
None of the above
36
Different objects at different distances are seen by the eye. The parameter that remains constant is
[A]
the focal length of the eye lens
[B]
the object distance from the eye lens
[C]
the radii of culvature of the eye lens
[D]
the image distance from the eye lens
Answer: the image distance from the eye lens
37
According to the theory of relativity, which of the following always remains constant?
[A]
Length of an object
[B]
Time
[C]
Space
[D]
Velocity of light
Answer: Velocity of light
38
A colour blind person cannot
[A]
see distant objects
[B]
see black colour
[C]
distinguished between certain colours
[D]
None of the above
Answer: distinguished between certain colours
39
A rear-view mirror for driving is
[A]
plain
[B]
concave
[C]
convex
[D]
inverted
40
In a laser (say neon laser) all the atoms emit the light waves of
[A]
same frequency
[B]
same amplitude
[C]
same phase
[D]
All of the above
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