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Question
State the nature and position of the object on the principal axis to obtain a real and magnified image.
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Solution
Lens is convex; the position of the object is between F and 2F.
RELATED QUESTIONS
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) |
Distinguish between a real and a virtual image.
For an object placed at a distance 20 cm in front of a convex lens, the image is at a distance 20 cm behind the lens. The focal length of the convex lens is ______.
State the condition of the following:
A lens has both its focal lengths equal.
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.
(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.
Name the subjective property of light related to its wavelength.
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.
Mixture of red + blue + green is passed through a convex lens as shown in the diagram below. State whether the ray passes through a single point or through different points on the principal axis after refraction.
