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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).
A ray of light after refraction through a lens emerges parallel to the principal axis of the lens. The incident ray either passes through ______.
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.
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 rrect choices in the following items :
An object is placed 50 cm from a connverging lens of focal length 30 cm. The image produced would be
(a)A ray of light is incident at 45° on the face of
(i) A rectangular block of glass.
(ii) A 600 glass prism.
(b) Draw a sketch showing how the ray of monochromatic ray of light passes through glass in each case.
(c) With the aid of a diagram, explain how the face of a right angled prism may totally reflect incident on it.
(d) A thick plane mirror produces several faint images in addition to a prominent one. Draw a ray diagram showing how reflection and refraction produce all these images.
(e) Fig. represents a stone S at the bottom of a pond of water. Using the two rays, as shown, complete the ray diagram to show where the image of the stone appears when viewed from E.
(f) What is a''mirage'? Explain with the help of a diagram.
(g) A man observes the bottom of a swimming pool of 3 m depth. If the refractive index of water is 1.3, what is the apparent depth of water?
(h) When a ray of light undergoes refraction through a glass slab and when it emerges it is displaced laterally (Fig). What are the factors on which the lateral displacement depends?
(i) Fig. shows three rays of light OA, OB and OC passing from water to air, making angles 490, 410 and 350 with the horizontal surface respectively. Draw an approximate path of the emergent ray for each. (Critical angle of water is 490.)
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.
When does a ray of light falling on a lens pass through it undeviated?
