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प्रश्न
Draw a ray diagram to show how a converging lens can form an image of the sun. Hence give a reason for the term ‘burning glass’ for a converging lens used in this manner.
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उत्तर
The sun is at infinity, so the convex lens forms its image at the second focal point, which is real and very much diminished in size.
While using the convex lens as burning glass, the rays of light from the sun (at infinity) are brought to focus on a piece of paper kept at the second focal plane of the lens. Due to the sufficient heat of the sun's rays, the paper burns. Hence, this lens is termed 'burning glass'.
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संबंधित प्रश्न
A lens forms an erect, magnified, and virtual image of an object. Draw a labelled ray diagram to show the image formation.
Draw a ray diagram to show how a converging lens can form a real and enlarged image of an object.
An object is placed at a distance of more than 40 cm from a convex lens of focal length 20 cm. The image formed is real, inverted and ______.
An object is placed at a distance 5 cm from a convex lens of focal length 10 cm. The image formed is virtual, upright and _____.
Where should an object be placed so that a real and inverted image of the same size is obtained by a convex lens?
A small bulb is placed at the principal focus of a convex lens. When the bulb is switched on, the lens will produce
An object is placed at a distance 20cm from a convex lens of focal length 10cm. Find the image distance and nature of the image.
An object of height 3cm is placed at 10cm from a concave lens of focal length 15cm. Find the size of the image.
A student focussed the image of a candle flame on a white screen using a convex lens. He noted down the position of the candle screen and the lens as under
Position of candle = 12.0 cm
Position of convex lens = 50.0 cm
Position of the screen = 88.0 cm
- What is the focal length of the convex lens?
- Where will the image be formed if he shifts the candle towards the lens at a position of 31.0 cm?
- What will be the nature of the image formed if he further shifts the candle towards the lens?
- Draw a ray diagram to show the formation of the image in case (iii) as said above.
A lens forms an upright and magnified image of an object. Draw a labelled ray diagram to show the image formation.
