10th Class Science Human Eye and Colourful World Question Bank

done Light and Human Eye Total Questions - 40

• question_answer1)
  Which of the following is called converging lens?
  A)
  Convex lens                   done clear
  B)
  Concave lens done clear
  C)
  Plane lens                      done clear
  D)
  Any lens done clear
  E)
  None of these done clear
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• question_answer2)
  Which of the following convex lenses will have greater magnifying power?
  A)
  Convex lens with focal length 10 done clear
  B)
  Convex lens with focal length 20 done clear
  C)
  Convex lens with focal length 15 done clear
  D)
  Convex lens with focal length 25 done clear
  E)
  None of these done clear
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• question_answer3)
  When an object is placed at the focus of the convex lens, the image will be formed at:
  A)
  Infinity done clear
  B)
  Twice the focal length done clear
  C)
  Focus of the lens done clear
  D)
  Between the optical centre of] lens and its Focus done clear
  E)
  None of these done clear
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• question_answer4)
  An object is placed at ____ distance from a convex lens of the focal length 10 cm to produce a real and smaller image.
  A)
  8 cm                 done clear
  B)
  10 cm done clear
  C)
  20 cm               done clear
  D)
  25 cm done clear
  E)
  None of these done clear
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• question_answer5)
  If an incident ray passes through the centre of curvature of a spherical mirror the reflected ray will be:
  A)
  Pass through the pole done clear
  B)
  Pass through the focus done clear
  C)
  Retrace its path done clear
  D)
  Parallel to the principal axis done clear
  E)
  None of these done clear
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• question_answer6)
  Which of the following types of images can be formed by a concave lens?
  A)
  An inverted magnified image done clear
  B)
  An erect magnified image done clear
  C)
  An erect diminished image done clear
  D)
  An inverted diminished image done clear
  E)
  None of these done clear
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• question_answer7)
  At what distance an object from a concave mirror having focal length of 20 cm should be placed so that the mirror forms a virtual image at 10 cm from the mirror?
  A)
  \[-12\text{ }cm\]             done clear
  B)
  \[-6.6\text{ }cm\] done clear
  C)
  \[-30\text{ }cm\]                         done clear
  D)
  \[-25\text{ }cm\] done clear
  E)
  None of these done clear
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• question_answer8)
  Which of the following is the power of convex lens having focal length 20 cm?
  A)
  4                                  done clear
  B)
  6 D done clear
  C)
  20 D                             done clear
  D)
  5 D done clear
  E)
  None of these done clear
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• question_answer9)
  What is the focal length of lens having power + 2D?
  A)
  20 cm               done clear
  B)
  25 cm done clear
  C)
  40 cm                           done clear
  D)
  50 cm done clear
  E)
  None of these done clear
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• question_answer10)
  The stars appear twinkling on a clear night due to:
  A)
  Reflection of light            done clear
  B)
  Refraction of light done clear
  C)
  Scattering of light done clear
  D)
         Both a and b done clear
  E)
  None of these done clear
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• question_answer11)
  The muscles of the iris control the:
  A)
  Focal length of the eye-lens done clear
  B)
  Amount of light entering the eye done clear
  C)
  Shape of the cyrstalline lens done clear
  D)
  Optic nerve done clear
  E)
  None of these done clear
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• question_answer12)
  When the eye is focused on an object very far away, then the focal length of the eye lens is:
  A)
  Maximum done clear
  B)
  Minimum done clear
  C)
  Half its maximum focal length done clear
  D)
  Equal to that of the crystalline done clear
  E)
  None of these done clear
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• question_answer13)
  Other names for myopia is:
  A)
  Near - sightedness           done clear
  B)
  Short- sightedness done clear
  C)
  Long - sightedness           done clear
  D)
  Both [a] and [b] done clear
  E)
  None of these done clear
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• question_answer14)
  Which phenomenon of light makes the sky look blue?
  A)
  Reflection                       done clear
  B)
  Refraction done clear
  C)
  Scattering          done clear
  D)
  Dispersion done clear
  E)
  None of these done clear
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• question_answer15)
  In the dispersion of white light, which of the following colour bends the least?
  A)
  Violet                done clear
  B)
  Red done clear
  C)
  Blue                              done clear
  D)
  Green done clear
  E)
  None of these done clear
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• question_answer16)
  The farthest point upto which the eye can see properly is called:
  A)
  Least distance of clear vision done clear
  B)
  Far point done clear
  C)
  Near point done clear
  D)
  Long- sightedness done clear
  E)
  None of these done clear
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• question_answer17)
  If the radius of curvature of a spherical mirror is 25 cm, what is its focal length?
  A)
  25 cm               done clear
  B)
  20 cm done clear
  C)
  12.5 cm done clear
  D)
  50 cm done clear
  E)
  None of these done clear
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• question_answer18)
  A highly enlarged image is obtained when:
  A)
  The object is placed at the focus in front of a convex mirror. done clear
  B)
  The object is placed at the infinity in front of concave mirror. done clear
  C)
  The object is placed at the focus in front of a concave mirror. done clear
  D)
  The object is placed at the centre of curvature in front of a concave mirror. done clear
  E)
  None of these done clear
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• question_answer19)
  Which of the following options is correct when an object of size 1 cm is placed at a distance of 20 cm from a concave mirror of focal length 15 cm.
  A)
  Nature: real and smaller, Image distance = 60 cm done clear
  B)
  Nature: virtual and enlarged, Image distance = 60 cm done clear
  C)
  Nature: real and enlarged, Image distance = 60 cm done clear
  D)
  Nature: virtual and smaller, Image distance = 60 cm done clear
  E)
  None of these done clear
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• question_answer20)
  Which of the following statements is correct?
  A)
  Hypermetropia is corrected by using convex lens. done clear
  B)
  Myopia is corrected by using concave lens. done clear
  C)
  Hypermetropia is also known as long-sightedness. done clear
  D)
  All the above done clear
  E)
  None of these done clear
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• question_answer21)
  A convex lens of focal length 4 cm forms a real image and same size as the object. The object is :
  A)
  Between F and 2F           done clear
  B)
  At 2F done clear
  C)
  At infinity                      done clear
  D)
  At focus done clear
  E)
  None of these done clear
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• question_answer22)
  Light enters from air into a glass plate having refractive index 2. What is the speed of light in glass? (The speed of light in vacuum is \[3\times l08\text{ }m/s\]).
  A)
  \[2\times {{10}^{8}}\text{ }m/s\]                      done clear
  B)
  \[3\times {{10}^{5}}\text{ }m/s\] done clear
  C)
  \[1.5\times {{10}^{8}}\text{ }m/s~~~~\]         done clear
  D)
  \[1.8\times {{10}^{5}}\text{ }m/s\] done clear
  E)
  None of these done clear
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• question_answer23)
  Which one of the following does not involve the use of convex lens?
  A)
  Making a simple camera. done clear
  B)
  Correcting the myopic eye defect. done clear
  C)
  Using as a magnifying glass. done clear
  D)
  All the above done clear
  E)
  None of these done clear
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• question_answer24)
  An object is placed at a distance of 25 cm from a convex lens of focal length 10 cm. The image produced will be:
  A)
  Magnified and real done clear
  B)
  Magnified and virtual done clear
  C)
  Of the same size as the object done clear
  D)
  Smaller and real done clear
  E)
  None of these done clear
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• question_answer25)
  Which of the following is used as an eye-lens in Galilean telescope?
  A)
  Concave mirror   done clear
  B)
  Convex Mirror done clear
  C)
  Convex lens                   done clear
  D)
  Concave lens done clear
  E)
  None of these done clear
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• question_answer26)
  Which of the following statements is incorrect?
  A)
  The focal length of a convex lens is considered positive done clear
  B)
  The focal length of convex mirror is considered positive done clear
  C)
  The power of convex lens is always negative done clear
  D)
  All the above done clear
  E)
  None of these done clear
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• question_answer27)
  When light is dim, the pupil becomes:
  A)
  Black                done clear
  B)
  Small done clear
  C)
  Large    done clear
  D)
  White done clear
  E)
  None of these done clear
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• question_answer28)
  In which of the following cases concave mirror is not used?
  A)
  To magnify the objects done clear
  B)
  In make - up mirror done clear
  C)
  In dentist's mirror done clear
  D)
  As rear - view mirror in vehicles done clear
  E)
  None of these done clear
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• question_answer29)
  Find the refractive index of a substance L. If the angle of incidence is \[72{}^\circ \] and the angle of refraction is \[90{}^\circ \]. (\[sin\text{ }72{}^\circ =0.951\])
  A)
  1.48                              done clear
  B)
  0.951 done clear
  C)
  1.951                done clear
  D)
  2.48 done clear
  E)
  None of these done clear
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• question_answer30)
  A pencil of 5 cm long is placed at a distance of 12 cm from a convex lens. Assuming it to be perpendicular to the principal axis, calculate the size of the image formed if the focal length of the lens is 8 cm.
  A)
  20 cm               done clear
  B)
  15 cm done clear
  C)
  10 cm               done clear
  D)
  12 cm done clear
  E)
  None of these done clear
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• question_answer31)
  The process of adjustment of focal length of eye lens is known as :
  A)
  Image formation done clear
  B)
  Accommodation done clear
  C)
  Lateral inversion done clear
  D)
  Dispersion done clear
  E)
  None of these done clear
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• question_answer32)
  In which of the following cases we get a virtual, erect and magnified image?
  A)
  When the magnification produced by a spherical lens is + 2. done clear
  B)
  When the magnification produced by a spherical lens is + 0.75. done clear
  C)
  When the height of image is negative and height of the object is positive in case of concave mirror. done clear
  D)
  All the above done clear
  E)
  None of these done clear
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• question_answer33)
  Which of the following statements is correct?
  A)
  A substance having higher refractive index is optically rarer. done clear
  B)
  A substance having lower refractive index is optically denser. done clear
  C)
  Kerosene is optically denser than water. done clear
  D)
  All the above done clear
  E)
  None of these done clear
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• question_answer34)
  ???????? is the instrument used to measure the power of a spectacle.
  A)
  Dioptremeter                  done clear
  B)
  Biometer done clear
  C)
  Ammeter                       done clear
  D)
  Anemometer done clear
  E)
  None of these done clear
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• question_answer35)
  Which of the following statements is correct?
  A)
  At blind spot in the eye is a place where more number of rods are present. done clear
  B)
  Focal length of the lens present in our eye is controlled by cornea. done clear
  C)
  The front part of the eye is called iris. done clear
  D)
  A virtual image is formed on retina present in human eye                done clear
  E)
  None of these done clear
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• question_answer36)
  The amount of light entering the eye is controlled by:
  A)
  Cornea              done clear
  B)
  Iris done clear
  C)
  Aqueous humour done clear
  D)
         Vitreous humour done clear
  E)
  None of these done clear
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• question_answer37)
  When an object is placed at a distance of 36 cm from a concave spherical mirror, the magnification produced is \[-\text{ }1/3\]. If image is formed at the same place where the object should be placed to get a magnification of \[-\text{ }1/4\]?
  A)
  \[-\text{ }12\,\,cm\]                     done clear
  B)
  \[-\text{ 48}\,\,cm\] done clear
  C)
  \[-\text{ 36}\,\,cm\]                     done clear
  D)
  \[-\text{ 50}\,\,cm\] done clear
  E)
  None of these done clear
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• question_answer38)
  Which of the following statements is correct if the magnification produced by the mirror is \[-\text{ }3\]?
  A)
  The image is erect and virtual. done clear
  B)
  The size of the image is one-third the size of the object. done clear
  C)
  The size of the image is thrice the size of the object. done clear
  D)
  All the above done clear
  E)
  None of these done clear
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• question_answer39)
  Magnification produced by a plane mirror is always equal to one because:
  A)
  Size of the image is twice the size of the object. done clear
  B)
  Size of the object is twice the size of the image. done clear
  C)
  Size of the object is equal to the size of the image. done clear
  D)
  Size of the image formed does not depend upon the size of the object. done clear
  E)
  None of these done clear
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• question_answer40)
  If the refractive index of glass is 1.5. Then the speed of light in glass is :
  A)
  \[2\times {{10}^{8}}m\,/s\] done clear
  B)
  \[3\times {{10}^{8}}m\,/s\] done clear
  C)
  \[1.071\times {{10}^{8}}m\,/s\] done clear
  D)
         \[1.28\times {{10}^{8}}m\,/s\] done clear
  E)
  None of these done clear
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