8th Class Science Light Question Bank

done Light Summative Subjective Problems Total Questions - 25

• question_answer1)
  When a light ray is incident normally on the surface of a plane mirror, the reflected ray deviates through an angle of _______.
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• question_answer2)
  What is the sum of angle of incidence, angle of reflection and angle of deviation equals to?
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• question_answer3)
  If the angle of deviation after reflection of a light ray is d, then find (a) Angle of incidence (b) Angle of reflection   (c) Angle of glancing
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• question_answer4)
  Keeping the incident ray constant, if a plane mirror is rotated through an angle \[\theta \], about an axis lying in its plane, then the reflected ray turns through an angle ________.
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• question_answer5)
  The angle between an incident ray and reflected ray for a given reflection is x. If the mirror is rotated through an angle x/2, keeping the incident ray constant, then find the angle between incident ray and reflected ray after rotation. Consider both clock wise and anticlock wise direction.
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• question_answer6)
  Keeping the plane mirror fixed, if the incident ray is rotated through an angle \[\theta \], then the angle through which the reflected ray rotates is ______.
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• question_answer7)
  A plane mirror lies face up, making an angle \[{{15}^{o}}\] with the horizontal. A ray of light shines down vertically on the mirror. What is the angle of incidence? What will be the angle between the reflected ray and the horizontal be?
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• question_answer8)
  If the reflected beam is convergent, ______ type of image is formed and if the reflected beam is divergent, then ______ type of image is formed.
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• question_answer9)
  A light bulb is placed between two mirrors inclined at an angle of \[{{60}^{o}}\]. The number of images formed are ____.
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• question_answer10)
  Two plane mirrors are kept at an angle of \[{{35}^{o}}\] to each other. A ray of light is incident on one of them at an angle of \[{{27}^{o}}\]. The angle of deviation is ____.
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• question_answer11)
  (i)  A person approaches a plane mirror with a velocity Y. He approaches his image with a velocity of ____. (ii) The distance between object and image formed by a plane mirror is 60 cm. If the object is moved away from the plane mirror by 15 cm, then the distance between object and image is ___.
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• question_answer12)
  Can a ray move from one medium to another medium, without bending. If so explain.
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• question_answer13)
  What is speed of light in diamond of refractive index 2.4, if the velocity of light in air is\[3\times {{10}^{8}}m/s\]?
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• question_answer14)
  An object 2.5 m high is placed in front of a pin hole camera. If the width of camera is 24 cm and size of image formed is 1.2 cm, find the distance of the object from pin hole camera.
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• question_answer15)
  The magnification of an image formed by a pin hole camera is 0.0005. If the object is at a distance of 500 m, calculate the distance of image from the pinhole.
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• question_answer16)
  In the above case, if the size of image is 2.4 cm, calculate the height of the object. m = 0.0005 Size of the image, I = 2.4 Size of the object, O = ?
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• question_answer17)
                  A ray of light is moving from air into medium. If the angle of incidence in air is \[{{45}^{o}}\] and angle of refraction is \[{{30}^{o}}\], then find the angle of deviation.
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• question_answer18)
  A ray of light is moving from air into medium. If the angle of incidence in air is \[{{45}^{o}}\] and angle of refraction is \[{{30}^{o}}\], then find the refractive index of the medium.
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• question_answer19)
  What is meant by power of accommodation of the eye?
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• question_answer20)
  A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision?
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• question_answer21)
  What is the far point and near point of the human eye with normal vision?
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• question_answer22)
  A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?
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• question_answer23)
  The human eye forms the image of an object at its (a) cornea                           (b) iris (b) pupil                               (d) retina
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• question_answer24)
  Why is a normal eye not able to see clearly the objects placed closer than 25 cm?
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• question_answer25)
  What happens to the image distance in the eye when we increase the distance of an object from the eye?
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