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рдкреНрд░рд╢реНрди
Yesh find out F1 and F2 of symmetric convex lens experimentally then which conclusion is true.
рд╡рд┐рдХрд▓реНрдк
a) ЁЭР╣1 = ЁЭР╣2
b) ЁЭР╣1 > ЁЭР╣2
c) ЁЭР╣1 < ЁЭР╣2
d) ЁЭР╣1 ≠ ЁЭР╣2
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рдЙрддреНрддрд░
a) ЁЭР╣1 = ЁЭР╣2
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When a ray of light enters from one medium to another having different optical densities it bends. Why does this phenomenon occur?
Complete the following table:
| Instrument | Number of Convex Lenses |
Use |
| Simple Microscope | .............. | .............. |
| Compound Microscope | .............. | .............. |
| Telescope | .............. | .............. |
A ray of light travelling in air is incident on a parallel-sided glass slab (or rectangular glass slab). Draw a ray-diagram indicating the change in its path in glass.
If an object is at a considerable distance (or infinity) in front of a convex lens, where is the image formed?
Distinguish between a convex lens and concave lens. Which of the two is a converging lens : convex lens of concave lens?
How could you find the focal length of a convex lens rapidly but approximately?
An object is placed f and 2f of a convex lens. Which of the following statements correctly describes its image?
(a) real, larger than the object
(b) erect, smaller than the object
(c) inverted, same size as object
(d) virtual, larger than the object
Find the position and nature of the image of an object 5 cm high and 10 cm in front of a convex lens of focal length 6 cm.
An object 50 cm tall is placed on the principal axis of a convex lens. Its 20 cm tall image is formed on the screen placed at a distance of 10 cm from the lens. Calculate the focal length of the lens.
Which type of lenses are:
thicker in the middle than at the edges?
A camera fitted with a lens of focal length 50 mm is being used to photograph a flower that is 5 cm in diameter. The flower is placed 20 cm in front of the camera lens.
At what distance from the film should the lens be adjusted to obtain a sharp image of the flower?
The diagrams (a) and (b) in Figure below show the refraction of a monochromatic ray of light through a parallel sided glass block and a prism respectively. In each diagram, label the incident, refracted emergent rays and the angle of deviation.
To find the image distance for varying object distances in case of a convex lens of focal length 15 cm, a student obtains on a screen a sharp image of a bright object by placing it at 20 cm distance from the lens. After that he gradually moves the object away from the lens and each time focuses the image on the screen.
(a) In which direction-towards or away from the lens does he move the screen to focus the object?
(b) How does the size of image change?
(c) Approximately at what distance does he obtain the image of magnification –1?
(d) How does the intensity of image change as the object moves farther and farther away from the lens?
Where must a point source of light be placed in front of a convex lens so as to obtain a parallel beam of light?
An object 4.0 cm in size, is placed 25.0 cm in front of a concave mirror of focal length 15.0 cm.
- At what distance from the mirror should a screen be placed in order to obtain a sharp image?
- Find the size of the image.
- Draw a ray diagram to show the formation of the image in this case.
State the position of object, position of image, nature of image when: Convex lens is used as objective lens of astronomical telescope.
State the position of object, position of image, nature of image when: Convex lens is used in cine projector.
We can burn a piece of paper by focussing the sun rays by using a particular type of lens. Name the type of lens used for the above purpose. Draw a ray diagram to support your answer.
_______ times larger images can be obtained by using a simple microscope.
The above image shows a thin lens with a focal length of 5m.
- What is the kind of lens shown in the above figure?
- If a real inverted image is to be formed by this lens at a distance of 7m from the optical centre, then show with calculation where should the object be placed.
- Draw a neatly labelled diagram of the image formation mentioned in (ii).
