Solar cells
Solar cells Coursework Aim I am trying to find out the relationship between light intensity and current produced by a solar cell and to explain how this happens. Background Research Solar cells need a sustainable amount of electricity to function properly. Solar cells transfer light energy into electrical energy. Although they involve no moving parts, they are high-tech solid-state devices. They are constructed by layered special materials called semi conducts; these are linked by electrical wires and arranged on a panel of glass (module). The panel will give out more energy depending light intensity it is getting. Light energy contains photons witch hit the solar panel and bump electrically charged particles around in the cell they then cause the electrons to move around and complete the circuit. This process repeats itself to give out energy. Prediction I think that when the light is moved further away than the solar cell the current will reduce because a solar cell needs light to create its current therefore without light it would not work. For example if it is moved four times, closer the solar cell will be 4 times more powerful. However if the Solar cell is moved four times further away then the current would of decreased and then stopped. Scientific Reason for Prediction I think this because if the power source is moved closer the light intensity will
Physics coursework
Physics coursework Jaypal Sandhu 12c Mr.Rugg How does different temperatures affect the resistance of a metal wire/thermistor. Aim (preliminary): The preliminary aim of my coursework was to measure what affect different temperatures have on the change in resistance of a copper wire. Apparatus: * Distilled water * Heat proof mat * Tri pod * Bunsen burner * Copper wire * 5v power pack * Electrical wires * Crocodile clips * Thermometer * 100? resistor Diagram: In theory this was a good experiment however in practice it was not. Whilst conducting the experiment I realise that from the temperature changing from 0 degrees to 100 degrees there was only a small change of 0.01v. I tried with a different resistor but still had no luck. There was not enough change for me to conduct a worthwhile experiment. I tried to use a higher current on the power pack but still the voltage never changed of the copper wire and as a higher current was used I ad to press the reset button as the power pack continued to reset. Therefore I concluded that using copper wire to conduct this experiment was not appropriate as it's resistively was too high to be affected by small or even large changes in temperature. Instead of using a metal I decided to use a thermistor as it can be subjected to different temperatures and I can expect some results Aim: The aim of my investigation is to see
Physics Coursework - Factors that affect the resistance of brine-soaked paper
Physics Coursework - Factors that affect the resistance of brine-soaked paper AIM I am trying to find out how different factors affect the resistance of brine-soaked paper. I will choose one factor and then do a series of experiments to try to find out how this factor affects the resistance. I have chosen to change the length of the paper. PREDICTION I think that when I increase the length of the paper, the resistance will also increase. When I increase the length, I predict that the resistance will also increase by the same amount making the relationship directly proportional. This is what I think the graph of final results will look like: I think this will happen because the resistance will drop when the length of the paper is reduced. This is because the ions have a shorter distance to travel through the liquid on the paper when it is a short piece of brine-soaked paper and therefore have less time and less in the paper to collide with the anything. Therefore when the paper is a long piece, the more ions there is, the more collisions that will be made and so the higher the resistance. The ions will need to work harder and will collide with more particles so the resistance will keep increasing every time the paper length is increased and therefore this will happen when double the paper length, the resistance will also double from before. PLAN In this investigation,
Organisational Change.
Organisational Change The one true test of an organisation is its ability to change to the seemingly random and turbulent business environment. A traditionalist view is to see the organisation as a living organism, and that it needs to evolve in order to ensure continued survival. Common focal points for change include: * Structure * Strategy * Culture * Technology * Job design The foundations of OC begin in looking at how change in the workplace can affect the individual, and how they can impact on the workplace. One of the key points in this area of research is with regards to Resistance to change, which is not restricted necessarily to any particular level of staff. Most emphasis on change results in problems that a manager may face, but considerations should also be given to behavioural patterns that may manifest as a result of resistance. Kanter (1983) observed that in many occurrences the behaviour of managers causes a suppressing effect, rather an encouraging one. O'Day (1978) identified a series of practices whereby managers may seek to discourage subordinates with proposition of change. He called these intimidation rituals, and they include (in order of execution); Nullification, Isolation, Defamation and Expulsion. Some of the reasons for opposition may include: * Innate dislike of change * Institutionalised practices * Threat to interests * Response
Electromagnet investigation
Tom Cole 11DSB-11R3 9061 25/6/02 Electromagnet investigation An electromagnet works similarly to a normal magnet but with one huge advantage. A normal magnet is constantly on but an electromagnet can be turned on and off. This is useful in both the science lab and industry such as a scrap yard. An industrial investigation of this size is obviously not possible in the science lab so in order to simulate a smaller type of situation I'm going to use small weights. I plan to find out the different characteristics of an electromagnet by changing the number of coils around the electromagnet and the amount of current which is passed through it. My hypothesis is that the amount of current and or coils which are placed on the magnet will govern the strength of the magnet. In order for the test to be fair I am going to have to make sure that some aspects stay the same and some are changed. I plan to change the CURRENT (AMPS) and the amount of coils wrapped around the core of the magnet. The factors which will remain the same are the voltage which I will set at 12V and the size of the iron core of the magnet. The investigation will require me to increase the amount of coils surrounding the iron bar. 100 coils will be the number I will use but this will change throughout the experiment. I also plan to see how much weight the electromagnet will hold. The weights which I
Electromagnetic Radiation.
Electromagnetic Radiation. The electromagnetic spectrum is the continuum of all electromagnetic waves arranged according to their frequency and wavelength. The spectrum is divided into regions based on their wavelength and proportionate energy. At the bottom of the spectrum are Gamma rays, which have the shortest wavelengths (less than 1x10^-12 m), and radio waves at the apex of the spectrum with extraordinarily long wavelengths that exceed a kilometre in length. While nearly all electromagnetic waves are invisible, there is a visible section that makes up, what normal people know as the colour spectrum. The sun, earth and other astrophysical bodies radiate electromagnetic energy in the form of a wave. These waves are given the name 'electromagnetic' because they are transmitted as a combination of varying electric and magnetic fields. These sinusoidal waves travel at right angles to each other and all at the same speed of 3x10^8 m/s in a vacuum. (electromagnetic wave) The fundamental behaviors of all the components of the electromagnetic spectrum are the same. The most obvious scientific difference is their varying wavelengths and frequencies and in the devices used to generate and detect them. All electromagnetic waves exhibit diffraction and interference as well as reflection and refraction. They also all obey the following equation: V
Electron Microscopes
Biology - Electron Microscopes Electron Microscopy is the use of Electron Microscopes. Electron Microscopes have a very high resolving power and a high magnification, and thus are used to view small objects with greater magnification and detail than a light microscope. There are two different types of electron microscopes, each with different abilities and limitations. This essay will analyse and discuss the functions and limitations of each different type individually, and then conclude with comparisons. Transmission Electron Microscope This type of electron microscope allows the user to view a 2d image of a cross section of a sample. It has a maximum resolution of 1 nm and a maximum magnification of 250,000 x. The good resolution is due to the short wavelengths of electrons, which is 0.005 nm. In a TEM the electrons are fired from an electron gun, which is part of the cathode, and are drawn through the microscope by the anode. The electrons pass through the specimen, which must be very thin, and prepared in a certain way for exactly that reason. The specimen preparation process will be explained in detail later in the essay. There are three electromagnetic lenses in a TEM. Electromagnetic lenses are used because firstly electron beams cannot pass through glass, and secondly, as electrons are charged particles, they are affected by a magnetic field. The first is called
Electron Microscopy.
Electron Microscopy. Electron microscopy is a method of imaging that uses an electron microscope to enlarge small specimens by a greater magnification and resolution than conventional light microscopes. The photographs produced of specimens viewed with an electron microscope are call electronmicrographs. Magnification is the increase in apparent size of the specimen and resolution (also called resolving power) is the ability of the microscope to distinguish and produce separate images of closely placed objects. These two primary properties of electron microscopes make them extremely useful in the analysis and study of specimens. The obvious difference between electron microscopes and light microscopes is the medium through which each operates. Light microscopes work by using photons to produce an image whereas electron microscopes use electrons to produce an image. The magnifying power of a light microscope is limited by the wavelength of visible light so electrons are used instead because they have a much smaller wavelength so can therefore resolve much smaller structures. The resolving power of a microscope depends on the wavelength of the electromagnetic radiation used. However, the benefits gained by using an electron microscope also bring specific problems that have to be tackled. Electron beams cannot pass through glass because electrons are physical matter.
Electron Microscopy.
Electron Microscopy An electron microscope can only show dead structures, but will show cell ultrastructure including the fine structure of the cell organelles. When using an electron microscope, the specimen is illuminated in an electron microscope by an electron beam. The electron beam is focused using electromagnets arranged around the path of the electron beam. These electrons then produce an image when focused onto a fluorescent screen. This image is formed from electrons, which have been emitted or reflected from the surface of a complete specimen. There are two different types of electron microscopes: a transmission electron microscope and a scanning electron microscope. The electrons pass through or past a thin section of the specimen in a TEM on their way to the fluorescent screen or photographic film. In SEMs the electrons are reflected off the prepared surface of the specimen. SEMs are very useful for detailed study of surfaces. They both have the same wavelength of 0.005nm, they both magnify non-living tissue specimens and they both produce a monochrome image. There are also some differences between them - the transmission electron microscope (TEM) requires a small copper grid as a support, whereas the scanning electron microscope (SEM) requires a small metal disk. Also, the TEM has a maximum magnification of 250,000 times, and the SEM has a maximum magnification
Electron microscopy.
Veronica Ouyang 12C Electron microscopy The development of the electron microscope (EM) has had a significant impact on science research. Invented in the 1930s, the present day version of the EM can magnify up to 500,000 times and has a resolution of about 1nm. In contrast, the light microscope can magnify an object by a maximum of 1500 times and the resolving power is 200nm. That means organelles, which are only blurred images when viewed with a light microscope, can now be studied in great details. Many new structures therefore have been discovered using the EM. Instead of using light, the EM uses a beam of electrons to resolve objects. The beam, which is produced by a heated filament, can be bent and focused by electromagnetic lenses, in the same way the glass lenses are used in a light microscope. The image is projected into a cathode ray tube, rather than the retina of the eye, to make it visible to the operator. When suitable sections are found, they are photographed to give a permanent record-an electron micrograph. The reason why the EM has higher resolving power is that the wavelength of the light used in light microscopes is around 500-650nm. This is much longer than which of the electrons is. That means two objects separated by less than 200nm will appear as one object for the light can not pass though, whereas electrons can. The EM includes two main types-the
