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प्रश्न
Object at 2F1 of a convex lens : Image at 2F2 : : Object at F1 : _______
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उत्तर
Object at 2F1 of a convex lens : Image at 2F2 : : Object at F1 : Image at infinity
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संबंधित प्रश्न
When a ray of light enters from one medium to another having different optical densities it bends. Why does this phenomenon occur?
An object of height 4.0 cm is placed at a distance of 30 cm from the optical centre 'O' of a convex lens of focal length 20 cm. Draw a ray diagram to find the position and size of the image formed. Mark optical centre 'O' and principal focus 'F' on the diagram. Also find the approximate ratio of size of the image to the size of the object.
Draw a labelled ray diagram to show the angle of incidence and the angle of refraction for a refracted ray of light.
For what position of an object a real, diminished image is formed by a convex lens?
Fill in the following blank with suitable word:
Parallel rays of light are refracted by a convex lens to a point called the ........
You eye contains a convex lens. Why is it unwise to look at the sun?
How could you find the focal length of a convex lens rapidly but approximately?
List some things that convex lens and concave mirror have in common.
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.
Rewrite the image distances in the correct order.
What type of images can a convex lens make?
A beam of parallel light rays is incident through the holes on one side of a box and emerges out through the holes on its opposite side as shown in the diagram below:
Which of the following could be inside the box?
(a) a rectangular glass block
(b) a concave lens
(c) a convex lens
(d) a glass prism
A lens forms an upright and magnified image of an object State whether the image is real or virtual
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.
State the position of object, position of image, nature of image when: Convex lens is used as in searchlight.
A concave mirror and convex lens are held in water. What changes, if any, do you expect in their focal length?
Diagram shows an object AB placed on the principal axis B of a convex lens placed in air. F1 and F2 are the two foci of the lens.
(i) Copy the diagram:
Draw a ray of light starting from B and passing through O. Show the same ray after refraction by the lens. Draw another ray from B which passes through F2 after refraction by the lens. Locate the final image
(ii) Is the image real or virtual?
_______ is a combination of two convex lenses with small focal length.
- In which type of microscope do you find the lens arrangement as shown in the following diagram?
- Write about the working and the use of this microscope.
