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प्रश्न
उत्तर
Choose a proper scale say, 4 cm = 1 cm. Mark the lens LPL' on the principal axis XX'. In front of the lens, Mark the object OA with distance OP = 24 cm and height of object OA = 4 cm.
For the object OA kept at a distance 24 cm in front of the convex lens of focal length 8 cm, the constuction of the image is shown in the figure. The distance PI of image IB, from the lens is 12 cm. thus the distance of image is 12cm. The image is real, inverted and dimnished(size 2.0 cm).
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संबंधित प्रश्न
An object of height 2.5 cm is placed at a distance of 15 cm from the optical centre 'O' of a convex lens of focal length 10 cm. Draw a ray diagram to find the position and size of the image formed. Mark optical 'O', principal focus F and height of the image on the diagram.
To find the image-distance for varying object-distances in case of a convex lens, a student obtains on a screen a sharp image of a bright object placed very far from the lens. After that he gradually moves the object towards the lens and each time focuses its image of the screen.
(a) In which direction – towards or away from the lens, does he move the screen to focus the object?
(b) What happens to the size of image – does it increase or decrease?
(c) What happen when he moves the object very close to the lens?
One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.
What is a lens?
Explain with the help of a diagram, why the convex lens is also called a converging lens.
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
A student did an experiment with a convex lens. He put an object at different distances 25 cm, 30 cm, 40 cm, 60 cm and 120 cm from the lens. In each case he measured the distance of the image from the lens. His results were 100 cm, 24 cm, 60 cm, 30 cm and 40 cm, respectively. Unfortunately his results are written in wrong order.
Which of the object distances gives the biggest image?
Which causes more bending (or more refraction) of light rays passing through it : a convex lens of long focal length or a convex lens of short focal length?
A student focussed the image of a distant object using a device ‘X’ on a white screen ‘S’ as shown in the figure. If the distance of the screen from the device is 40 cm, select the correct statement about the device.
(A) The device X is a convex lens of focal length 20 cm.
(B) The device X is a concave mirror of focal length 40 cm.
(C) The device X is a convex mirror of radius of curvature 40 cm.
(D) The device X is a convex lens of focal length 40 cm.
Find the odd one out and give its explanation.
