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प्रश्न
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.

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उत्तर
The completed ray diagram is shown.

(i) The lens formed by the combination is the convex lens.
(ii) The line XX’ is called the principal axis.
(iii) The focus has been marked by the letter F in the diagram.
संबंधित प्रश्न
What is a lens?
Explain optical centre of a lens with the help of proper diagram(s).
In the following figure (a) and (b), F1 and F2 are positions of the two foci of thin lenses. Draw the path taken by the light ray AB after it emerges from each lens.
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| (a) |
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| (b) |
Study the diagram shown in Fig. 5.56
Complete the diagram to show the formation of image A’B’ of the object AB of same size.

The diagram given below shows the position of an object OA in relation to a converging lens whose foci are at F1 and F2.

Describe how the distance of the image from the lens and the size of the image 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.

Make the correct choices in the following items:
lf the image can be focused on a screen it must be
Make the correct choices in the following items :
The image formed by a diverging lens, shown in fig, , is

(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.)



