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Question
Where must a point source of light be placed in front of a convex lens so as to obtain a parallel beam of light?
Solution
At focus:
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RELATED QUESTIONS
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?
Fill in the following blank with suitable word:
Parallel rays of light are refracted by a convex lens to a point called the ........
Distinguish between a convex lens and concave lens. Which of the two is a converging lens : convex lens of concave lens?
Define principal axis, principal focus and focal length of a convex lens.
List some things that convex lens and concave mirror have in common.
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?
What kind of lens is used to correct
long-sightedness?
A lens always forms an image between the object and the lens.
A lens always forms an image between the object and the lens.
In the figure given below L is a convex lens, M is a plane mirror and S is a point source of light. Rays of light from the source S return to their point of origin. Complete the ray diagram to show this. What is the point S called?
Distinguish between:
Concave lens and Convex lens
