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प्रश्न
Where must a point source of light be placed in front of a convex lens so as to obtain a parallel beam of light?
उत्तर
At focus:
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संबंधित प्रश्न
Which of the following lenses would you prefer to use while reading small letters found in a dictionary?
What is a lens?
Draw a ray diagram to show the formation of a real magnified image by a convex lens. (In your sketch the position of object and image with respect to the principal focus of lens should be shown clearly).
In a certain murder investigation, it was important to discover whether the victim was long-sighted or short-sighted. How could a detective decide by examining his spectacles?
i. Which type of microscope has the arrangement of lenses shown in the adjoining figure?
ii. Label the figure correctly.
iii. Write the working of this microscope.
iv. Where does this microscope used?
v. Suggest a way to increase the efficiency of this microscope.
A pin 2 cm long is placed 12 cm away from a convex lens at right angles to the principal axis. If the focal length of the lens is 20 cm, by scale drawing find the size of the image and its magnification.
Write the three characteristics of the image formed by a convex lens of focal length 20 cm for the object at distance (i) 10 cm, (ii) 30 cm, (iii) 40 cm, (iv) 60 cm from the lens.
Draw a diagram to show the convergent action of a convex lens by treating it as a combination of glass block and two triangular glass prisms, with the aid of two parallel incident rays.
An object is placed in front of a convex lens such that the image formed has the same size as that of the object. Draw a ray diagram to illustrate this.
Distinguish between Concave lens and Convex lens.
