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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 ______.
विकल्प
its optical centre
its first focus
its second focus
its centre of curvature of the first surface
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उत्तर
A ray of light after refraction through a lens emerges parallel to the principal axis of the lens. The incident ray either passes through its first focus.
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संबंधित प्रश्न
What is a lens?
Explain optical centre of a lens with the help of proper diagram(s).
State the condition when a lens is called an equi-convex or equi-concave.
In figure, (a) and (b), F1 and F2 are the two foci of thin lenses and AB is the incident ray. Complete the diagram to show the path of the ray AB after refraction through each lens.
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| (a) |
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| (b) |
The diagram given below shows the position of an object OA in relation to a converging lens L whose foci are at F1 and F2.
- Draw two rays to locate the position of the image.
- State the position of the image with reference to the lens.
- Describe three characteristics of the image.
- Describe how the distance of the image from the lens and its size change as the object is moved towards F1.
What type of lenses are used in spectacles worn by an old lady for knitting?
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.
Fig. shows two rays of light Op and OQ coming from an object at the bottom of a pond, incident on the water surface.
(a) Mark on the diagram
(i) The angle of incidence of ray OP,
(ii) The angle of refraction of ray Op,
(iii) The position of image of the object as seen from above.
(iv) An approximate path of the ray OQ.
(b) Explain, why do the rays of light change directions on passing from water to air.
(c) A fish in water sees everything outside the water by rays of light entering its eye in a small cone of light. Draw a diagram and explain how does this happen.
State the nature and position of the object on the principal axis to obtain a real and magnified image.
