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प्रश्न
Distinguish between a real and a virtual image.
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उत्तर
| Real image | Virtual image |
| 1. A real image is formed due to actual intersection of refracted (or reflected) rays | 1. A virtual image is formed when the refracted (or reflected) rays meet if they are produced backwards |
| 2. 2 A real image can be obtained on a screen | 2. 2. A virtual image cannot be obtained on a screen |
| 3. 3. A real image is inverted with respect to the object. | 3. 3. A virtual image is erect with respect to the object |
संबंधित प्रश्न
Explain optical centre of a lens with the help of proper diagram(s).
In the diagram below, XX’ represents the principal axis, O the optical centre and F the focus of the lens. Complete the path of rays A and B as they emerge out of the lens.
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| (a) | (b) |
Study the diagram shown in Fig. 5.56
Where is the image formed?
A ray of light incident parallel to the principal axis of a lens, passes undeviated after refraction.
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 :
The image formed by a diverging lens, shown in fig, , is
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.
