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Refraction By Lens Free Doubts and Solutions

Derive lens formula for concave lens and state lens formula.

Asked by polyrelation 15th March 2019, 4:40 PM

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Derive lens formula for concave lens and state lens formula.

Asked by polyrelation 15th March 2019, 4:40 PM

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please solve the question in the picture. Asked by rohitraman1115 12th January 2019, 12:19 PM

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WHAT IS THE RAY DIAGRAM OF CONCAVE LENS WHEN OBJECT IS PLACED AT FOCUS? PLEASE EXPLAIN IN DETAIL

Asked by modi72879 7th November 2017, 9:42 AM

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WHAT IS THE RAY DIAGRAM OF CONCAVE LENS WHEN OBJECT IS PLACED AT INFINITY? PLEASE EXPLAIN IN DETAIL

Asked by modi72879 7th November 2017, 9:41 AM

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Ans with explanation Asked by Varsneya Srinivas 20th October 2017, 8:42 PM

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If the image formed in cinema is real then shouldn't it be inverted, and how do they avoid it?

Asked by nileshpatel19752000 13th October 2017, 11:52 PM

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Find power Asked by bijuaylara111 8th September 2017, 12:15 AM

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what is the power and focal length of sunglasses?

Asked by vasturushi 7th September 2017, 10:42 AM

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How do we determine with which type of lens our spectacles are made? According to the type of eye disordres how do the spectacle makers design them?

Asked by pksunilnair 26th April 2017, 10:22 AM

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briefly explain mathematically how the focal length of a concave lens will change when it is cut    a) vertically   at the middle b) horizontally at the middle

Asked by ppratim02 12th July 2016, 4:56 PM

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briefly explain  mathematically how the focal length of a  convex lens  will change when it is  cut  vertically at the middle

Asked by ppratim02 12th July 2016, 4:54 PM

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An equiconvex lens is cut into two identical plano convex lens. What is the ratio of focal lengths of equiconvex lens to that of plano convex lens...?

Asked by nayonikamenon15 11th January 2016, 12:33 AM

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draw a ray diagram to show the image formation in refraccting type astronomical telescope in the normal adjusment  when image is formed at infinity.derive an expression the aperture of objective lens and why?

Asked by mahamood.iphone 14th December 2015, 9:53 PM

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what will be the focal lenght of the lens if radii of curvature of two surfaces were equal in magnitude and also had the same sign?

Asked by Jahanvi 8th October 2015, 7:41 PM

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What is the relation between focal length and radius of curvature of a lens?Do the two focal lenghs of a lens  always have the same value?Are the focal lengths of a lens different for different medium?

Asked by joykphukan 21st July 2015, 9:13 PM

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The focal length of an equiconvex lens is equal to the radius of curvature of either face. What is the refractive index of the material of the lens?

Asked by Topperlearning User 8th July 2015, 11:31 AM

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Q.56 The figure shows a convergent lens placed inside a cell filled with a liquid. The lens has a focal length +20 cm, when in air and its material has refractive index 1.5. if the liquid has a refractive index 1.6, the focal length of the system is a) +80 cm b) –80 cm c) –24 cm d) –160 cm

Asked by Malavika Umesh 5th May 2015, 6:16 PM

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an object is placed 12cm to the left of a converging lens of focal length 8cm.Another converging lens of 6cm focal length is placed at a distance of 30cm to the right of the first lens.Th e second lens will produce a)no image b)a virtual enlarged image c)a real enlarged image d)a real inverted image

Asked by Malavika Umesh 29th April 2015, 12:14 PM

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A thin plano-convex lens acts like a concave mirror of focal length 0.2m when silvered from its plane surface.THe refractive index of the material of the lens is 1.5. What will be The radius of curvature of the convex surface of the lens??

Asked by Malavika Umesh 26th April 2015, 10:46 PM

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Q.On a convex lens ,light of red and violet colour is incident separately , then how does the focal length of lens change?

Asked by Ravi consul 4th March 2015, 6:48 PM

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A concave lens of glass, refractive index 1.5, has both surface of the same radius of curvature R. On immersion in a medium of refractive index 1.75, it will

Asked by yashu.fly 22nd November 2014, 10:18 PM

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1. The focal length of an equiconvex lens in air is equal to either of its radii of curvature. the refractive index of the material of lens is __________ 2. A charge of 4x10^-8C is uniformly distributed over the surface of sphere radius 1cm. another hollow sphere of radius 5cm is concentric with the small sphere. find intensity of electric field at a distance 2cm from centre. [K=9x10^9 MKS] [ans in NC^-1] 3. A light of 4560angstrom and 1mW is made incident on photosensitive surface of Cs. If efficiency of surface is 0.1%, then photoelectric current produces is___________ 4.A spherical drop of water has 3x10^-10C charge on its surface. 300 volt electric potential exists on its surface. if 27 such identical drops are combined to form a single drop, calculate electric potential on the surface of new drop._____________

Asked by Dhriti 24th October 2014, 12:10 PM

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1. The focal length of an equiconvex lens in air is equal to either of its radii of curvature. the refractive index of the material of lens is __________ 2. A charge of 4x10^-8C is uniformly distributed over the surface of sphere radius 1cm. another hollow sphere of radius 5cm is concentric with the small sphere. find intensity of electric field at a distance 2cm from centre. [K=9x10^9 MKS] [ans in NC^-1] 3. A light of 4560angstrom and 1mW is made incident on photosensitive surface of Cs. If efficiency of surface is 0.1%, then photoelectric current produces is___________ 4.A spherical drop of water has 3x10^-10C charge on its surface. 300 volt electric potential exists on its surface. if 27 such identical drops are combined to form a single drop, calculate electric potential on the surface of new drop._____________

Asked by Dhriti 24th October 2014, 12:10 PM

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can u plzz explain the difference of  sign conventions in  the cases  of reflection and refraction in both concave and convex lense as well as mirrors  also diffrence of sign convention in case of magnfication. it is not clear to through notes .kindly answer this question as quikly as possible ..........

Asked by NAVYA SOOD 19th July 2014, 8:57 PM

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Draw a ray diagram to show the formation of real image of the same size as that of the object placed in front of a converging lens. Using this ray diagram establish the relation between u, v and f for this lens. OR Derive the lens formula for a concave lens, using the necessary ray diagram.

Asked by Topperlearning User 8th July 2014, 1:39 PM

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There are n number of lenses of focal length f 1 , f 2 ,....fn in contact. What is the focal length and the power of the combination.

Asked by Topperlearning User 10th June 2014, 9:48 AM

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A convex lens has a focal length of 30cm. An object is placed at a distance of 20cm from the lens. What is the nature of image formed by refraction at lens?

Asked by Topperlearning User 10th June 2014, 9:45 AM

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A convex lens behaves as converging lens when dipped in water whereas it behaves as diverging lens when dipped in carbon disulphide . Why?

Asked by Topperlearning User 10th June 2014, 9:28 AM

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Glass of refractive index 1.55 is used to manufacture a double convex lens with the same radii of curvature R. For the focal length of lens to be 25 cm, what is the radius of curvature?

Asked by Topperlearning User 10th June 2014, 9:16 AM

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A pin placed 40 cm from a lens forms an image on a screen placed at 80 cm on the other side of the lens. Determine the type of lens, focal length of lens.

Asked by Topperlearning User 10th June 2014, 8:58 AM

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There is a convex air bubble in a tank of water. State its behavior as a lens.

Asked by Topperlearning User 10th June 2014, 8:55 AM

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Two lenses of power 10 D and -5 D are placed in contact. (i) Calculate the power of lens combination. (ii) Where should an object be held from the lens, so as to obtain a virtual image of magnification 2 ?

Asked by Topperlearning User 10th June 2014, 7:52 AM

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The image of an object formed by a lens on the screen is not in sharp focus. Suggest a method to get clear focussing of the image on the screen without disturbing the position of the object, the lens or the screen.

Asked by Topperlearning User 10th June 2014, 7:20 AM

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A convex lens of refractive index 1.5 has a focal length of 18 cm in air. Calculate the change in its focal length when it is immersed in water of refractive index .

Asked by Topperlearning User 4th June 2014, 1:23 PM

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A convex lens made up of glass of refractive index 1.5 is dipped, in turn, in: (i) Medium A of refractive index 1.65 (ii) Medium B of refractive index 1.33 Explain, giving reasons, whether it will behave as a converging lens or a diverging lens in each of these two media.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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A convex lens of focal length 30 cm is placed coaxially in contact with a concave lens of focal length 40 cm. Determine the power of the combination. Will the system be converging or diverging in nature?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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The radii of curvature of the faces of a double convex lens are 10 cm and 15 cm. If focal length of the lens is 12 cm, find the refractive index of the material of the lens.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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Violet light is incident on a thin convex lens. If this light is replaced by red light , explain with reason, how the power of the lens would change ?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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A figure divided into squares, each of size 1mm2, is being viewed at a distance of 9 cm through a magnifying lens of focal length 10 cm, held close to the eye. (a) Draw a ray diagram showing the formation of the image. (b) what is the magnification produced by the lens ? How much is the area of each square in the virtual image? (c) What is the angular magnification of the lens ?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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Two thin lenses of focal length 5 cm and 10 cm are placed in contact. What will be the focal length of the combination?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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A combination of two thin lenses has a power of +10D. If one of the concave lens has a focal length 1/4m. Find the nature and power of other lens.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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The power of a lens is (i) +6D and (ii) -2D what is the focal length and nature of lens?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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A lens has a focal length of -30cm. What is the nature and power of the lens?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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State the conditions under which the concave lens behave as a converging lens.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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Suppose a lens has different radii of curvature, it forms an image of an object placed on its axis. If we reverse the lens will the position of the image of the object change?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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The refractive index of concave lens is 1.2. This lens is immersed in a liquid of refractive index 1.4. Explain the behavior of the lens.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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The image of a small electric bulb fixed on wall of a room is to be obtained on opposite wall of a room 3m away by means of large convex lens. What is the maximum possible focal length of the lens required for this purpose?

Asked by Sourav Naval 1st June 2014, 1:53 PM

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Write thin lens formula for a convex lens and draw the graph showing the variation of u and v for a convex lens.

Asked by Topperlearning User 22nd May 2014, 3:29 PM

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Calculate the focal length of the combination o f a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm. Is the system a converging or a diverging lens ?

Asked by Topperlearning User 22nd May 2014, 2:05 PM

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What is the magnification if n number of lenses are used to magnify an object?

Asked by Topperlearning User 22nd May 2014, 1:25 PM

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What is dioptre?

Asked by Topperlearning User 22nd May 2014, 1:20 PM

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Why do we combine two or more lenses?

Asked by Topperlearning User 22nd May 2014, 1:18 PM

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Focal length of a convex lens is 25cm. Calculate the power of the lens?

Asked by Topperlearning User 22nd May 2014, 12:59 PM

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A +4D glass lens is immersed in water completely. What will be the effect on lens's power?

Asked by Topperlearning User 22nd May 2014, 12:56 PM

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Radius of curvature of a plano-convex lens of glass () is 25 cm. What is the focal length?

Asked by Topperlearning User 22nd May 2014, 9:57 AM

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explain and derive lens makers formula.

Asked by Sagar krishna 16th May 2014, 6:39 PM