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प्रश्न
Define the term focus of a lens.
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उत्तर
The focus of a lens (often called the principal focus) is a specific point on its principal axis where light rays parallel to the axis either converge or appear to originate from after passing through the lens.
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संबंधित प्रश्न
A ray of light after refraction through a lens emerges parallel to the principal axis of the lens. The incident ray either passes through ______.
A ray of light incident on a lens parallel to its principal axis, after refraction passes through or appears to come from ______.
In the following diagram , the object and the image formed by the respective lenses are shown. Complete the ray diagram, and locate the focus. Find the focal length of the lens.
In the following diagram , the object and the image formed by the respective lenses are shown. Complete the ray diagram, and locate the focus. Find the focal length of the lens.
Make the correct choices in the following items :
A lens used as a magnifying glass
(i) ls a diverging lens
(ii) Produces a virtual image
(iii) ls placed with the object nearer the lens than the principle focus
Make the correct choices in the following items :
The image formed by a diverging lens, shown in fig, , is
The diagram showed a lens as a combination of one glass block and two prisms. Complete the ray diagram and show the part of the incident ray AB after passing through the lens.
(i) Name of the lens formed by the combination.
(ii) What is the line XX’ called?
(iii) Mark the focus F.
Complete the following diagram and state what happens to the ray of light after refraction through the lens.
In the following diagram, L1 and L2 are the two convex lense placed at separation equal to the sum of focal lengths of the two lenses. A and B are the two rays of light incident on the lens L1. Complete the path of rays till they emerge out of the lens L2.
What principles have you used in completing the diagram?
