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प्रश्न
What is the position of image when an object is placed at a distance of 10 cm from a convex lens of focal length 10 cm?
उत्तर
Given:
Object distance, u = -10 cm
(Since object is always placed on the left side of lens)
Focal length, f = +10 cm
According to lens formula:
`1/v-1/u=1/f`
`1/v=1/f+1/u`
`1/v=1/10=(-1/10)=0`
`v=1/0= oo`
Therefore, the position of image will be at infinity.
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संबंधित प्रश्न
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?
An object is placed at a distance of 15 cm from a concave lens of focal length 30 cm. List four characteristics (nature, position, etc.) of the image formed by the lens.
The diagram given alongside shows a ray of light entering a rectangular block of glass.
(a) Copy the diagram and draw the normal at the point of entry.
(b) Draw the approximate path of the ray of light through the glass block and out of the other side.
Define principal axis, principal focus and focal length of a convex lens.
An object 4 cm high is placed at a distance of 10 cm from a convex lens of focal length 20 cm. Find the position, nature and size of the image.
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.
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.
Which part causes the greatest convergence?
State two applications of a convex lens.
Distinguish between:
Concave lens and Convex lens
