Design an experiment to predict and test the output from a simple AC generator.
Design an experiment to predict and test the output from a simple AC generator. Planning A simple ac generator will produce an alternating emf of magnitude V0 and frequency f. The AC generator is shown below, A manufacturer of AC generators has asked you to help design a clockwork torch of peak power 1W. The bulb is powered by a hand driven AC generator that is rotated at 2Hz. It is assumed that the light bulb has a constant resistance once in use because it doesn't have time to cool down as the current alternates. The manufacturer has provided you with a horseshoe magnet of approximate field strength 50mT and gap 20cm, a selection of commercially available reels of copper wire of different diameters and the light bulb. The rest of the material necessary to build the generator is provided by the school. The coil ABCD is square. Using classroom apparatus you must plan experiments to; a] Determine the unknown properties of the magnet, copper wire and bulb. b] Test the final constructed version. You will need to find the relevant Physics to explain, ] The factors affecting the peak emf in an ideal generator and how these can be measured. 2] The factors affecting the peak current in an ideal generator and how these can be measured. You will need to carry out research into; i] Commercially available bulbs and wire to give reasonable relevant values for calculations.
Physics Coursework Gravity Investigation
PLANNING: Aim: To investigate the efficiency of the bounce of a golf ball at different release heights. Scientific knowledge: In this experiment, the golf ball used will have undergone several types of energy transfers from the time of release to the time it reaches its' bounce height. From the moment the golf ball is lifted from the floor, it contains gravitational potential energy (G.P.E). Therefore, the golf ball must contain gravitational potential energy when held at a release height. The formula for gravitational potential energy is: G.P.E = Mass × Gravity × Height It is clear that the formula is made of three measurements, mass, gravity and height. The mass of the golf ball would have been kept constant throughout the experiment, simply by using the same ball. Gravity is equal to, 9.81ms-2 on earth. Therefore, gravity remained the same throughout the experiment. The final measurement in the formula, height, doesn't remain the same as there were different release heights. With this in mind, if the value for mass and gravity remain the same but the height varies, then the gravitational potential energy must vary with the heights. If the release height increases, the gravitational potential energy increases. For example, if the release height of the golf ball doubled, the gravitational potential energy of the golf ball would also double. The release height is
Resistance Investigation
Resistance Investigation Aim An electronics factory needs resistors of 5 ohms and 15 ohms for a new electrical device. My task is to investigate how the resistance of a piece of wire depends on length and to find the length of the wire needed to make the required resistors, using only 4 volts. Introduction/Planning A selection of different wires made from constantan and nichrome and the usual laboratory apparatus will be available for me. Wire A - Constantan wire of approximate diameter 0.3mm Wire B - Constantan wire of approximate diameter 0.4mm Wire C - Constantan wire of approximate diameter 0.3mm A constantan is an alloy whose resistance stays fairly constant when it becomes hot. In fact the resistance changes by less than 0.5% even when the temperature rises by a few hundred degrees. Nichrome, along with other metals, is an alloy whose temperature does change appreciably when it becomes hot. Before starting my coursework, I have to find the variables in the experiment, safety aspects etc. I found that a number of things affect the resistance of a wire. Below is a list of factors and reasons why they affect the resistance of a wire. From this list of factors I have to make sure that these factors remain constant or excluded from the experiment. We are only investigating length but the other variables may change our outcomes. In electricity, resistance is the
Factors affecting Resistance of a wire
Factors affecting Resistance In preliminary work, I wanted to find out which factors affect resistance. In some research I found that there were four factors. The four factors of resistance are: * Temperature: If the wire is heated up the atoms in the wire will start to vibrate because of their increase in energy. This causes more collisions between the electrons and the atoms as the atoms are moving into the path of the electrons. This increase in collisions means that there will be an increase in resistance. * Material: The type of material will affect the amount of free electrons, which are able to flow through the wire. The number of electrons depends on the amount of electrons in the outer energy shell of the atoms, so if there are more or larger atoms then there must be more electrons available. If the material has a high number of atoms there will be high number of electrons causing a lower resistance because of the increase in the number of electrons. Also if the atoms in the material are closely packed then the electrons will have more frequent collisions and the resistance will increase. * Wire length: If the length of the wire is increased then the resistance will also increase as the electrons will have a longer distance to travel and so more collisions will occur. Due to this the length increase should be proportional to the resistance increase. * Wire
The resistance of a wire.
Prediction I predict that if the length increases then the resistance will also increase in proportion to the length. I think this because the longer the wire the more atoms and so the more likely the electrons are going to collide with the atoms. So if the length is doubled the resistance should also double. This is because if the length is doubled the number of atoms will also double resulting in twice the number of collisions slowing the electrons down and increasing the resistance. My graph should show that the length is proportional to the resistance. The diagrams below show my prediction and should explain it more clearly: Conclusion In my prediction I said that : ¡§¡K.if the length increases than the resistance will also increase in proportion to the length.¡¨ From my graph I have shown that my prediction was correct, as the Line of Best Fit is a straight line proving that the resistance of the wire is proportional to the length of the wire. The length of the wire affects the resistance of the wire because the number of atoms in the wire increases or decreases as the length of the wire increases or decreases in proportion. The resistance of a wire depends on the number of collisions the electrons have with the atoms of the material , so if there is a larger number of atoms there will be a larger number of collisions which will increase the
Draw stress and strain graphs for the metal copper and the alloy constantan. Calculate the figures of young's modulus for copper and constantan. Discuss the physics involved.
AS Physics Data Analysis coursework This coursework assignment requires me analyse and evaluate data on copper and constantan given to me. It entails investigating the young's modulus of the metal and alloy. Thus I will use many methods during to complete my investigation. Aims: . To draw stress and strain graphs for the metal copper and the alloy constantan 2. To calculate the figures of young's modulus for copper and constantan 3. To discuss the physics involved Plan: In this investigation I have received results for extension of copper and constantan for certain forces applied to it, for which I will analyse and calculate the young's modulus. The results I have been given are forces applied to copper and constantan, three sets of results for the metal and alloy and this can be used by averaging data to give more accurate results thus these results given to me will be used to create graphs, calculate young's modulus and analyse data for both metals so I can complete my investigation. I will need to draw a force and extension graph for both copper and constantan, the extension shown will be the averaged value for each metal. I will also calculate the stress and strain values and plot this on a graph for both copper and constantan, I will plot these on the same graph and analyse the graph, hence I can find any patterns from the data and this will require me to draw
Investigate the resistance of a wire at different stages on the power supply.
Planning This is the part of my coursework where I am going to plan an experiment that I am to analyse for my work. What we are going to do is to investigate the affects or the variables have on different lengths of constantan wire. I am going to use different lengths which will provide me with a range of results. The reason I want a range of results is so that I can compare and analyse results, which will let me evaluate the readings clearly. First I will tell you a little about how I started. We were set into groups with other pupils, and then together we set out and did our preliminary experiment. The preliminary experiment is very important, because it is like a practice for the real thing. Also it helps as here you can make mistakes, so when doing the real experiment errors can be eliminated. I will explain how we did the preliminary experiment and include all the steps we took. For my introduction I want to start off by just explaining a little about the material that we are using, as this is vital so we know what is harmful and what is not, which can help with safety. The power supply - we will be using one of these. This can be dangerous if not used safely. We should know that the power supply should not b left on for more than a few seconds, with certain wires, as it can blow the system. When plugging the plug in, you must make sure the switch is off. This may
The Efficiency of an Electric Motor.
The Efficiency of an Electric Motor Aim: To investigate how the efficiency of an electric motor varies when it is lifting different weights. Summary: I have investigated how the efficiency of an electric motor varies when it is lifting different weights. I found that the efficiency of my motor (using an input voltage of 4v) was maximum when it was lifting 500-800g weights. I also found that the efficiency of the motor depended on its internal resistance and friction. I also used my results to estimate the internal resistance of the motor and I found it was about 0.5? In my extension experiment I used the electric motor as a generator. I dropped a variety of weights from my pulley system and I measured the amount of energy produced using a joule meter. I found that the efficiency of the generator increased as the mass of the weight I dropped increased. The percentage efficiency of the generator also appeared to tend towards 14%. Finally I discussed whether my experiment was time reversible. I decided that it was to an extent but not completely. I decided this since I only retrieved about 1-2% of the energy I used to lift the weight when I dropped the weight again, using the motor as a generator. Experiment 1: See Diagram1 for Apparatus and circuit diagram Experimental Method: I will use a 12v electric motor to lift a variety of weights a fixed height and I will
The factors affecting the resistance of a metalic conductor.
INVESTIGATION: THE FACTORS AFFECTING THE RESISTANCE OF A METALLIC CONDUCTOR Metals conduct electricity because the electrons in the metal can move about inside the structure. These electrons are called free electrons. Electricity is conducted through a conductor by means of free electrons. Atoms consist of protons, electrons and neutrons. The protons and neutrons make the nucleus of an atom while the electrons circle the outer area of the atom. Electrons in metal are able to move freely and are used as current in an electric circuit. This is because they carry a charge and can move all around the circuit with this charge. While these electrons are travelling around the circuit, atoms are sometimes in the way, causing the two to collide. This takes out some of the energy from the electron and transfers it to the atom. This is how resistance occurs. The number of free electrons depends on the material and the more the free electrons in a substance the better the material as a conductor. All conductors offer resistance to the flow of current. The conductor's atoms determine this resistance. For example copper atoms offer negligible resistance to an electric current because a significant proportion of its electrons are free to move from electron to electron. Thus copper is commonly used as a conductor. Current, is the flow of electrons around a circuit. Those materials,
Molecular stability (rheology) of a plastic carrier bag through stress - strain tests.
.0 Introduction I am going to study the molecular stability (rheology) of a plastic carrier bag through stress - strain tests. I will do this through a simple viscoelastic experiment of where I will be able to calculate the Young Modulus and assess Hooke's Law. Plastic carrier bags are made from polyethylene or 'polyethene', which is a 'homopolymer'. Polyethylene comes from ethylene. Ethylene is an alkane made up of a series of saturated hydrocarbons. "The alkane series are known as homologous series" as they share the properties and general formula: (CnH2n+2) .1 Origin of plastic Essentially plastics are materials that can be heated and moulded and maintains this moulded shape once it cools. Plastics have existed since the beginning of time. Plastic contains 'natural' elements such as carbon(C), hydrogen (H), nitrogen (N), chlorine (Cl) and sulphur (S). These elements can be 'originated' from naturally grown organic materials such as wood, horn and rosin. Animal horn and amber are examples of natural plastics. Already renown for his work in the rubber industry, Alexander Parkes invented a material that was based on cellulose nitrate at the Great Exposition of 1862 in London. He called this material Parkesine, which was the first synthetic polymer. His invention was due to a new scientific movement to utilise by-products of natural gas production. We are now in the
