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Lenses MCQs | Lenses Multiple Choice Questions and Answers

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Questions
1 In the case of a concave mirror, the image of an object is
A Real, erect and diminished when the object lies beyond the centre of curvature
B Real, inverted and of the same size as the object when it lies between the centre of curvature and focus
C Real, inverted and diminished when the object lies beyond the centre of curvature
D Not real, large and unproportional

Answer: Real, inverted and diminished when the object lies beyond the centre of curvature
2 To increase the magnifying power of a telescope, the focal length of
A Objective lens should be increased
B Objective lens should be decreased
C Eye-piece lens should be increased
D Eye-piece lens should be decreased

Answer: Eye-piece lens should be decreased
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3 Which of the following is used to split white light into different colours?
A Glass slab
B Convex lens
C Concave lens
D Prism

Answer: Prism
4 'Short-sight' in human eye can be corrected by using proper
A convex lens
B concave lens
C cylindrical lens
D bifocal lens

Answer: concave lens
5 Which one of the following lenses should be used to correct the defect of astigmatism?
A Cylindrical lens
B Concave lens
C Convex lens
D Bifocal lens

Answer: Cylindrical lens
6 A mirage occurs because of
A reflection by hot ground
B total internal reflection by layers of air
C interference of light
D diffraction of light

Answer: total internal reflection by layers of air
7 A periscope works on the principal of
A refraction
B total internal reflection
C diffraction
D reflection

Answer: total internal reflection
8 Which of the following is incorrect?
A A concave mirror can give a magnified virtual image
B A concave mirror can give a magnified real image
C The virtual image given by a concave mirror is inverted
D The real image given by a concave mirror is inverted

Answer: The virtual image given by a concave mirror is inverted
9 What would be the number of images formed of an object in two mirrors placed at right angles to each other?
A two
B three
C four
D six

Answer: three
10 The head mirror used by E.N.T doctors is -
A Concave
B Convex
C Plane
D Plano-convex

Answer: Concave
11 How far must an object be from a concave mirror if the image formed is to be inverted?
A less than its focal length
B exactly at its focal length
C more than its focal length
D None of the above

Answer: more than its focal length
12 How far must a girl stand in front of a concave spherical mirror of radius 120 cm to see an erect image of her face four times its natural size?
A 40 cm from the mirror
B 45 cm from the mirror
C 50 cm from the mirror
D 55 cm from the mirror

Answer: 45 cm from the mirror
13 The human eye is like a camera and hence it contains a system of lens. The eye lens forms
A a straight or upright, real image of the object on the retina
B an inverted, virtual image of the object on the retina
C an inverted, real image of the object on the retina
D a straight or upright, real image of the object on the iris

Answer: an inverted, real image of the object on the retina
14 The ratio of the focal length of the objective to the focal length of the eyepiece is greater than one for
A a microscope
B a telescope
C both microscope and telescope
D neither microscope nor telescope

Answer: a telescope
15 Which one among the following is used to make periscope?
A Concave lens
B Concave mirror
C Plane mirror
D None of the above

Answer: Plane mirror
16 What type of a mirror is used in anti-shop-lifting-devices?
A Concave mirror
B Convex mirror
C Plane mirror
D None of the above

Answer: Convex mirror
17 Due to which phenomena the stick if immersed in water appears to be bent?
A Reflection
B Dispersion
C Refraction
D Scattering

Answer: Refraction
18 What is the power of concave lens?
A Positive
B Negative
C Both
D None of the above

Answer: Negative
19 In projectors which lenses are used?
A Convex lens
B Concave lens
C Bipolar lens
D Both (a) and (b)

Answer: Convex lens
20 Due to which phenomena light rays emerging from a cinema machine spread wide on the screen?
A Dispersion
B Diffraction
C Scattering
D Refraction

Answer: Diffraction
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