# Focal length of a concave lens experiment. Concave Lens 2022-10-16

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The focal length of a lens is a measure of how strongly the lens will converge or diverge light. It is an important parameter in the design of lenses for a variety of applications, such as eyeglasses, cameras, and telescopes.

One way to experimentally determine the focal length of a lens is to use a concave lens and a screen. A concave lens is a lens that is thinner at the center than at the edges, and it is used to diverge light.

To set up the experiment, a light source, such as a lamp or flashlight, is placed at one end of a table. The concave lens is then placed on the table at a distance from the light source. A screen is placed at the other end of the table, and the distance from the lens to the screen is measured.

The distance from the lens to the light source is varied, and the resulting image of the light source on the screen is observed. As the distance from the lens to the light source increases, the image on the screen becomes smaller and more focused. When the distance from the lens to the light source is at a minimum, the image on the screen is at its largest and least focused.

The focal length of the lens can then be calculated using the lens equation, which relates the distance from the lens to the light source, the distance from the lens to the screen, and the focal length of the lens.

Focal length = (Distance from lens to screen x Distance from lens to light source) / (Distance from lens to screen + Distance from lens to light source)

By repeating this experiment for different distances between the lens and the light source and measuring the resulting image on the screen, the focal length of the concave lens can be determined with a good degree of accuracy.

In conclusion, the focal length of a concave lens can be experimentally determined by setting up a light source, a concave lens, and a screen and measuring the resulting image on the screen. The focal length can then be calculated using the lens equation, which relates the distances between the lens, the light source, and the screen. This experiment is a simple and effective way to determine the focal length of a concave lens and can be used in a variety of applications.

## Determining the Focal Length of a Convex Lens Experiment

Thus, only a concave mirror or a convex lens can be used. Fix the convex lens in the middle of the optical bench and place one pin on either side of it. An eye is placed at a distance of 3 f to the right of the lens and a distance h below the optic axis. What are the use of lens? The 5 sets of u,v values recorded by the student in cm are: 42 , 56 , 48 , 48 , 60 , 40 , 66 , 33 and 78 , 39. The coordinates of a point object and its image are -40cm,1cm and 50cm,-2cm , respectively. This will give the focal length of the mirror. Justify this using mirror formula? How To Set Up 1.

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## Determination of Focal Length of a Concave Mirror

A concave lens with a more focal length 4. When an object is at distances x and y from a lens, a real image and a virtual image is formed respectively having same magnification. How to Find the Focal Length of Convex Lens? Amrita OLabs YouTube Video. The graph obtained will be a rectangular parabola. Good webpage at www. Apparatus 2 meter rules, a light box, a white-coloured screen, a D. This point of meeting is the focal point.

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## To find focal length of concave lens using convex lens

The particular length has played important role in the experiment of concave and convex lens. The u,v pairs with calculated values of v are 42 , 56 , 48 , 48 , 60 , 40 , 66 , 37. If an object is placed at a distance 2 f from the pole then its image is formed at a distance 2 f from the pole on the other side. It is designed as thick from the edges and thin from the center. Put the concave lens in contact with the convex lens. In general, the concept of parallax is memorized by the students without understanding it.

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## Focal Length of Concave Lens Experiment

Keep the distance between the plane mirror and convex lens as 30cm 40cm for other set of. Hence, the object is near to the pole P in comparison to its image. The screen should be vertical. Measure the distance between the screen. The readers are encouraged to draw ray diagram and show that image is complete. Here a bench is the most essential material and two needles are required here.

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## PHY260 LAB REPORT: DETERMINING THE FOCAL LENGTH OF A CONVEX LENS

F uv u v cm From this formula we get the way to find the focal length of a convex lensfind focal length of a. At the very first stage, the determination of the rough focal length of the convex lens is done. The flame of the candle should be at the same height as the pole of the lens. THEORY: The focal length of lens, f is related to the object distance, p and image distance, q according to the lens equation. On the other hand, the point B, which is far from the eye, appears to move in the direction of eye movement. Adjust the centre of the lens and the tips of the pins in the same horizontal line. Distances measured in the direction of the incident ray are positive and the distances measured in the direction opposite to that of the incident rays are negative.

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## Determination Of Focal Length Of Concave Mirror And Convex Lens

Forming the image of a distant object on the wall. For one position of the lens the magnification of the image obtained on the screen is m 1. Now, fix the mirror at the distance u which is obtained as 1. If it makes a diminished image, change the convex lens with another one of shorter focal length. Conclusion: The focal length of a lens can be defined as the distance between the lens and its principal focus. Two lens holders 5.

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## Focal length of Concave and Convex lens

The distances are measured from the pole P. Then plot a graph with U and V to find out the focal length of the lens by applying the equation. Theory Since the convex and concave lenses are made of glasses, the focal lengths are actually the convergent point of all refracted light sources. Before starting with the main topic, here are a few terms that must be understood first. The distance between the focus and the optical center of a lens is called the focal length.

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## Focal length of a concave mirror

The focal length of a concave mirror is negative in sign if we consider the traditional sign convention rule for the mirror and lens. Different factors can affect the lens' power such as the thickness of the length. Determination Of Focal Length Of Concave Mirror And Convex Lens Byju S Experiments To Measure The Focal Length Of A Converging Lens Physics Homework Help Physics Assignments And Projects Help Assignments Tutors Online To Determine The Focal Length Of A Convex Lens By Focusing A Distant Object Youtube Determination Of The Focal Length Of A Convex Lens Uv Method Youtube Practical Ways Ways To Find The Principal Focal Length Len Write Down In Four Steps How To Find Out The Focal Length Of A Convex Lens Experimentally In The Lab You have just read the article entitled Determining the Focal Length of a Convex Lens Experiment. In this experiment, some materials are needed and they are essential for this examination. Another required material is a half-meter scale.

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## Determination of Focal Length Of Concave Lens Using Convex Lens

Focal Length of a Convex Lens A convex lens is shown above. Thus, u, v and f are all negative by sign convention. This distance is the approximate focal length f of the mirror. Now to obtain the focal length of the combination lens we have the following. The image needle and object needle are no longer in line. Another factor is that in the time of removing the parallax the removal must not be perfect.

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## To Find Focal Length of Concave Lens Using Convex lens

Now, measure the distance from the center of mirror pole to that point. For this purpose, it was important to know the focal length of the lenses to combine their powers. Get the focal length from all measurements by a taking average of calculated f or b from u versus v graph or c from versus graph. Focal Length of Convex Lens Experiment. The screen should be vertical.

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