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प्रश्न
State the condition of the following:
A lens has both its focal lengths equal.
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उत्तर
If the medium on both sides of the lens is same, the first and second focal lengths are equal.
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संबंधित प्रश्न
Study the diagram shown in Fig. 5.56
where is the object located?
A ray of light incident at the optical centre of lens, passes undeviated after refraction.
State the condition of the following:
A ray passes undeviated through the lens.
Fig shows an object PQ placed on the principle axis of a lens L. The two foci of the kens are F1 and f2. The image formed by the lens is erect, Virtual and dimnished.
(i) Draw the outline ofthe lens L used and Named it.
(ii) Draw a ray of light starting from Q and passing through O. show the same ray after refraction by the lens.
(iii) Draw another ray from Q Which is incident parallel to the principle axis and show how it emerges after refraction from the lens.
(iv) Locate the final image formed.
Define the term focus of a lens.
A lens forms the image of an object placed at a distance of 45 cm from it on a screen placed at a distance 90 cm on the other side of it. Name the kind of lens.
How will you differentiate between a convex and a concave lens by looking at a printed page?
State the nature and position of the object on the principal axis to obtain a real and magnified image.
Complete the following diagram and state what happens to the ray of light after refraction through the lens.
Draw a ray diagram to show the image formed by a convex lens when the object is placed between F and 2F.
