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प्रश्न
Object at 2F1 of a convex lens : Image at 2F2 : : Object at F1 : _______
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उत्तर
Object at 2F1 of a convex lens : Image at 2F2 : : Object at F1 : Image at infinity
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संबंधित प्रश्न
An object is placed at a distance of 12 cm from a convex lens of focal length 8 cm. Find :
1) the position of the image
2) nature of the image
A ray of light travelling in air is incident on a parallel-sided glass slab (or rectangular glass slab). Draw a ray-diagram indicating the change in its path in glass.
Draw a labelled ray diagram to show the angle of incidence and the angle of refraction for a refracted ray of light.
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?
Describe with the help of a ray diagram the nature, size and position of the image formed when an object is placed at infinity (considerable distance) in front of a convex lens. State three characteristics of the image so formed.
What type of lens is shown in the diagram on the right? What will happen to the parallel rays of light? Show by completing the ray diagram.
A burning candle whose flame is 1.5 cm tall is placed at a certain distance in front of a convex lens. An image of candle flame is received on a white screen kept behind the lens. The image of flame also measures 1.5 cm. If f is the focal length of convex lens, the candle is placed:
(a) at f
(b) between f and 2f
(c) at 2f
(d) beyond 2f
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.
What would be the image distance if the object distance was 90 cm?
Complete the following sentence.
A long-sighted person cannot see ........... objects clearly. Long-sightedness can be corrected by using .............. lenses.
The diagram alongside shows the refraction of a ray of light from sir to a liquid.
(a) write the values of (i) angle of incidence, (ii) angle of refraction.
(b) use snell’s law to find the refractive index of liquid with respect to air.
The given below figure shows an object OA and its image IB formed by a lens. State three characteristics of the image.
A lens forms an inverted image of an object. Name the kind of lens.
In the following cases, where must an object be placed in front of a convex lens so that the image formed is inverted and enlarged?
An object is placed perpendicular to the principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 30 cm. Find (i) the position (ii) the magnification and (iii) the nature of the image formed.
Answer the following question.
List four precautions which a student should observe while determining the focal length of a given convex lens by obtaining an image of a distant object on a screen.
State the position of object, position of image, nature of image when: Convex lens is used as an erecting lens in terrestrial telescope.
State the position of object, position of image, nature of image when: Convex lens is used in cine projector.
In sunglasses, both of its surfaces are curved, yet their behaviour is neither like a convex lens nor like a concave lens. State the reason.
A beam of light is incident through the holes on side A and emerges out of the holes on the other face of the box as show in the figure. Which of the following could be inside the box?
