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Lenses MCQs | Lenses Multiple Choice Questions and Answers

(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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