Relationship Between U and V For a Convex Lens
SC 1 Relationship between u and v for a convex lens Prediction I think that when the length of 'u' increases (object distance), the length 'v' will decrease. (image distance.) Only when the object is greater than the focal length of the lens, is a real image is produced. If the object distance is nearer the focal length than a virtual image is produced. The virtual image has a negative distance from the lens, which means it can't be focused onto the screen. When plotting my results on graph, I will expect them to produce a curved line for u over v, producing a reciprocal graph. However a straight line when plotting 1/u over 1/v. Scientific Ideas This formulae for the focal length of an object: /focal length = 1/object distance + 1/image distance The following formulas are rearranged from the one above. This will help me throught my experiment, and with my scientific ideas. u = object distance f = focal length v = image distance (20.0 cm) (15.0 cm) (60.0 cm) f = 1 / (1/u + 1/v) 15 = 1 / (1/20 + 1/60) (FOCAL LENGTH) f = (uv) / (u + v) 15 = (20*60) / (20 + 60) u = 1 / (1/f - 1/v) 20 = 1 / (0.06 - 0.016) (OBJECT DISTANCE) u = (vf) / (v-f) 20 = (60*15) / (60-15) v = 1 / (1/f - 1/u) 60 = 1 / (0.06 - 0.05) (IMAGE DISTANCE) v = (uf) / (u-f) 60 = (20*15) / (20-15) FOCAL LENGTH = 15 cm u (cm) v (cm) 0.00 - 30.00 20.00 60.00 30.00 30.00
aspects of physics
Aspects of Physics in the Grove leisure Centre Automatic door system Pool lighting Purpose of each one Automatic door system The purpose is for the doors to open automatically when anyone is a certain distance from the door. The distance should be right for when they are walking up to the door so it has enough time to open when the person is close enough to go through it. The automatic door is needed for disabled access as it is a legal requirement. The grove has had them since the year 2000 because legal reasons state that all public places have to have access for disabled people. It makes it a lot easier for school parties, so the teacher doesn't have to hold the door so they can make sure the children at the front of the queue are looked after and not left unattended. Some people who are medically referred to the leisure centre by their doctors might be very weak and wouldn't be able to open a door, so an automatic door overcomes this problem. Another helpful thing is that the doors will not be left open in winter time, and therefore will not let heat out, which in turn will save money as the building will not need excess heating because heat is being lost. Pool Lighting The lights are not located directly above the swimming pool, the main reason for this is that it would be extremely hard to fix and change them; another reason is that if the lights were directly
How to treat Cataracts.
CATARACTS Normal Vision Eye with Cataracts A cataract is a clouding of the natural lens, the part of the eye responsible for focusing light and producing clear, sharp images. The lens is contained in a sealed bag or capsule. As old cells die they become trapped within the capsule. Over time, the cells accumulate causing the lens to cloud, making images look blurred or fuzzy. The light rays are refracted off their normal path onto the back part of the eye making the objects appear out of focus. TREATMENT Phacoemulsification During surgery, a special instrument breaks apart the old Lens with Ultrasound. The pieces of the Lens are then removed. This process is called Phacoemulsification. The cloudy Lens is then removed through a small incision and replaced with a clear, artificial Intraocula Lens (IOL). Extracapsular Surgery During Extracapsular Surgery, an incision slightly larger than for Phacoemulsification is made in the eye and the Lens Nucleus is removed, leaving the rear Capsule of the lens intact. Leaving the Posterior Capsule reduces the risk of complications later on. The Intraocula Lens is then implanted behind the Iris. Posterior Chamber Lens Implant A Posterior Chamber Lens Implant is similar to a contact lens, with one big difference: The Intraocula Lens is an internal and permanent part of the Eye. An Intraocula Lens is
Measuring the focal length of a lens for red and green light- Case Study
Measuring the focal length of a lens for red and green light- Case Study The case study that I will be studying is how the focal length of a lens for red and green light differs. Eye defects is not something that is new it has been occurring for many years. Corrective lenses were said to be used by Abbas Ibn Firnas in the 9th century. Around 1284 in Italy, Salvino D'Armate is credited with inventing the first wearable eye glasses. Focal length and optics both are related to the eyes. The eyes are used to see things without the eyes we would not know where we are going or what anything looks like. The diagram to the left shows a diagram of the eye. http://kidshealth.org/kid/htbw/eyes.html The image above is of the human eye. The way the human eye works is that light enters the eye passing thro the iris, pupil and cornea. Once it reaches the lens of the eye the lens refracts the light further and it is made to converge at a single point at the back of the eye where the retina is. Once this happens the optical nerve sends messages to the brain and it is the brain that actually converts this to an image for us to see. The lens of an eye works in a similar way to a converging lens. A converging lens refracts light that passes through it to a single point; this is known as the focal point. The diagram below shows some information on the focal point and focal length:
Investigating the relationship between the image distance and the object distance for a convex lens
Investigating the relationship between the image distance and the object distance for a convex lens FAIR TESTING In this experiment I will be changing two factors which will be the object distance and the image distance. The following factors that are going to be kept constant are:- . The positioning of the image and light source - if this is changed; it could affect the results and may give anomoulous results. The light source must also point at the image and directly at the convex lens. 2. The convex lens - if the size of this convex lens is change; it could again affect the results and may give anomoulous results. 3. The light source - The intensity of the light source needs to be kept the same to prevent any anomoulous results. 4. The bulb watt - this would have to be kept constant, i.e. if I use double the watt of the bulb than my overall outcome of results is will doubled. APPARATUS LIST To perform this experiment I will need some apparatus. This will consist of:- * 30cm ruler * 1m ruler * A Pencil * Blank A4 piece of paper * Connecting wires x2 * Convex Lens * Light bulb * Power meter DIAGRAM Below is a labelled diagram of how the experiment is going to be set-up:- METHOD This is the procedure that I will use to do the experiment:- . Set up apparatus as in shown in the diagram. 2. Turn on the power. 3. Measure the object distance 4. Measure
Lenses - experiment plan
Lenses Introduction Lenses are a transparent material shaped to refract light. Lenses are remarkable and have helped mankind develop in the so many years the world now uses for almost and visual activity from swimming goggles to open heart surgery lenses are used in some form. But lenses are not all the same. There are two main types of lenses convex and concave. These two lenses are opposites of each other and produce different images. Concave lenses are rarer to find in every day life. A concave lens is curved inwards it is shaped like two dishes placed back-to-back. Light passing through a concave lens diverges. Unlike convex lenses, which produce real images, concave lenses produce only virtual images. A virtual image is one from which light rays only appear to come from but in actual fact the do not. This appears as a smaller to produce image just in front of the actual object. Concave lenses are generally prescribed for short-sighted, people. Concave lenses help the eyes to produce a sharp image on the retina instead of in front of it. Convex lenses are more common in everyday life. The lens is very thick in the middle and thinner at the edges. With the unique shape of then lens it causes the lens to converge any light rays that pass through. This produces an image on any surface on the other side of the lens. The human eye lens is a convex lens and is more like
This essay is on vision, its malfunctions & diagnostics methods.
Vision, its malfunctions & diagnostic methods By Jaswinder Singh .0 Preface This essay is on vision, its malfunctions & diagnostics methods. The content included is concordant with the criteria listed on the specification of the institute of biophysics at 2nd Faculty of Charles University in Prague. Additional acknowledgements are mentioned under the reference section. .1 Visual acuity and its measurement Visual acuity is the measurement of the ability to discriminate two stimuli separated in space at high contrast relative to the background1; it is a quantitative measure of the ability to identify black symbols on a white background at a standardized distance as the size of the symbols is varied. It happens to be the most common clinical measurement of visual function. Visual acuity is typically measured using optotype chart for close and distant vision (snellen test). The eye which is not under test is occluded by means of instructing the subject to place an obstacle, for example a hand in front of the eye. This prevents intentional peeking, which would adversely affect the validity of the examination results. A variety of charts convenient for the patient are used, particularly in cases where a subject is unable to read the alphabet. In such cases the Tumbling E chart may be used, where the perceived letter, capital ''E'' is facing a different direction.
Describe the principles and limitations of transmission and scanning electron microscopes. Specific reference should be made to magnification and resolution
Describe the principles and limitations of transmission and scanning electron microscopes.Specific reference should be made to magnification and resolution Introduction Microscopy has a major role in cytology.From the very beginning researchers have tried to develop ways of looking directly at living cells.This examination has revealed much about the morphology of cells and tissues.In recent years,development in microscopes,dyes,staining and preparatory techniques have helped reveal even more about the structure and function of cells.Microscopes have a certain magnification and resolving power.In any microscope the the resolving power is more important than the magnification.The resolving power of a microscope is the least distance between two objects where the microscope can still distinguish the objects as being separate.It is a measure of detail that can be seen.A microscope with a high resolving power enables us to view images with a high resolution.With a low resolution they would be viewed as one object.Microscopes with a high magnification are only able to increase the size of the object that is being viewed.The resolution will be the same.(ie the object will still lack clarity and appear fuzzy).The two types of microscopes are electron and light microscopes. Principles and Limitations of light microscopy Light microscopes function by focussing a beam of light on
The Principles and Limitations of Electron Microscopy.
The Principles and Limitations of Electron Microscopy. An Electron Microscope is a type of microscope that makes use of a beam of electrons rather than visible light. Which is due to the fact that the wavelength of electrons is much smaller than the wavelength of visible light, an Electron Microscope not only gives a high magnification but it also has high resolution. This means that details can be seen clearly. An Electron Microscope is very similar to a Light Microscope in the ways in which it works but, instead of using glass lenses to focus a beam of light, it uses magnets to focus a beam of electrons. Electrons are very small, so they are scattered if they hit molecules in the air due to this they must travel through a vacuum. Specimens that are to be examined must be cut into very thin sections, and these must be treated so that they can be examined in these conditions. The variety of chemical processes that are carried out in this preparation may change the appearance considerably. Features which have been introduced in this way are known as artefacts and care needs to be taken in interpreting electron micrographs because of the possible presence of artefacts. An examination of a specimen using an Electron Microscope can yield the following information: Topography: The surface features of an object or "how it looks", it's texture; direct relation between these
Research into Telescopes
Telescopes The first record of a device that acted like a telescope was made in October 1608. It came from Holland where the state discussed the patent applications of Hans Lipperhey and Jacob Metius. The records describe a device for "seeing faraway things as though nearby." It was the most simple form of telescope consisting of a tube and a concave lens at one end and a convex lens at the other and gave a magnifying power of three or four times. The earliest known illlustration of a telescope. Giovanpattista della Porta included this sketch in a letter written in August 1609 But the man who made telescopes really famous was Galileo Galilei. By October/November 1609 he had constructed a 24x telescope and made observations of the moon and discovered the four major moons of Jupiter. Galileo's telescopes were simple refracting telescopes that were of less quality than those you can buy cheaply in the high street. They were based on simple convex lens to focus the light and magnify that image. Convex lens's work on the principle of refraction. When a wave enters a material that is denser than the original substance, it 'bends' towards the normal (the normal being perpendicular to the plane the denser material). The opposite occurs when the wave leaves the denser material. Upon leaving the denser material the wave is 'bent' away from the normal. This is called