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प्रश्न
How will you differentiate between a convex and a concave lens by looking at a printed page?
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उत्तर
On keeping the lens near a printed page, if the letters appear magnified, then the lens is convex, and if the letters appear diminished, then the lens is concave.
संबंधित प्रश्न
What is a lens?
A ray of light after refraction through a lens emerges parallel to the principal axis of the lens. The incident ray either passes through ______.
Distinguish between a real and a virtual image.
State the condition of the following:
A lens has both its focal lengths equal.
State the condition of the following:
A ray passes undeviated through the lens.
(a) Draw a sketch to show how a lens is able to produce an image of the sun on a paper screen.
(b)(i) Would you regard the rays from the sun as being divergent, parallel or convergent?
(ii) What is the name given to the point where such rays meet after they have passed through the lens?
(iii) How does the image of the sun sometimes burn a paper screen?
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 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.
Complete the following diagram and state what happens to the ray of light after refraction through the lens.
Draw a ray diagram to show the image formed by a convex lens when the object is placed between F and 2F.
