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Ray Optics and Optical Instruments — Physics STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 SciencePhysicsRay Optics and Optical Instruments1 Mark
Question
Two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion: A convex lens is made of two different materials. A point object is placed on the principal axis. The number of images formed by the lens will be two.
Reason: The image formed by convex lens is always virtual.
✓

Answer

  1. A is true but R is false.

Explanation:

Since thelensis made of two different materials of different refractive indices, there will be two different focal lengths of the lens. Hence two images will be fanned. The image fanned by convex lens is always real except in case when object is placed between optical centre and focus.

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