What Is Fibre Optics
WHAT IS FIBRE OPTICS? To put it simply, fibre optics is a technology whereby a signal like video, data or voice, is concentrated on a light beam and sent down a glass tube over large distances, with very little distortion and loss. The principles of fibre optics are simple and easy to understand. All of us have seen the "broken straw" effect in a glass of water. When light travels from air to a denser medium, like glass for example, the light slows down by a factor equal to the optical index of the material and this slow down in speed results in bending of the light. As shown in the example when we see an object from underwater, the object is not in the actual position as we think because light bends travelling from water to air. When this angle of entry is increased, there would come a stage when the light is reflected back into the same medium, as shown in ray 3. This angle is called the angle of Total Reflection. Fibre Optics uses this simple principle for transmission. The core of the fibre optics cable, which is made of glass, has a higher index of refraction than the index of the cladding, which covers this core. So when light is injected into the glass core at the correct angle, it will reflect back from the surface and continue doing this in its forward direction of travel. In other words the light cannot "escape" from the fibre. COMPONENTS OF A FIBRE OPTICS
Investigation in resistance in wires
Investigating Resistance in Wires Aim In this investigation I will be looking into the theory of resistance and current in wires; this theory is called Ohms Law. By doing the experiments I will be hoping to prove Ohms law correct, and testing to see if it remains constant as the voltage, and wire lengths vary. Related Theory Resistance is measured in ohms (), resistance can be calculated by using the formula V = I × R V = voltage measured in volts (V) I = current measured in amps (A) R = resistance measured in ohms () This is the formula called Ohms Law. Ohms law is the relationship between voltage, current and resistance. For a metal conductor at a constant temperature the current is directly proportional to the voltage. This means that if the current increases the voltage will also increase in the same proportion. For example: If a cell provides a voltage of 1 volt and the circuit has a resistor of 1 ohm connected to it an ammeter would read 1 amp. If the cell was replaced with a 2 Volt cell the ammeter would read 2 Amps. Resistance is caused by electrons bumping into ions. If the length of the wire is doubled, the electrons bump into twice as many ions so there will be twice as much resistance. If the cross-sectional area of the wire doubles there will be twice as many ions and twice as many electrons bumping into them, but also twice as many electrons getting
Investigation of the response of a microphone / loudspeaker over a range of frequencies
Investigation of the response of a microphone/loudspeaker over a range of frequencies Aim & Hypothesis To become proficient with using a signal generator and a Cathode Ray Oscilloscope (CRO.) Also, to investigate how the amplitude of a signal from a microphone varies as the frequency of a fixed amplitude signal applied to the loudspeaker varies, (between 100Hz and 1000Hz.) Safety RISK ASSESSMENT - LEVEL ONE This experiment does not carry many hazards. Bags and coats will be moved out of the way to ensure that no one will trip over them. The only other potential danger is as a result of using mains operated equipment. I will not be using the equipment near any water, taps etc. I will do a visual check on the equipment before use (not fraying or lose wires, etc.) Variables Independent Variable: Frequency (Hz) Dependent Variable: Amplitude (mV) I will be using the signal generator to alter the frequency being produced - therefore this will be the independent variable. This will alter the amplitude of the wave being shown on the CRO so this is the independent variable. I have used the same equipment throughout the experiment in order to ensure a fair test. Diagram Method The apparatus was set up as shown on the previous page. Firstly I did three 'checks' to ensure that (to check if they are properly calibrated.): * The amplitude of the signal remains constant *
How does the power dissipated by a light bulb vary with voltage?
How does the power dissipated by a light bulb vary with voltage? Plan Introduction For my experiment, I am going to investigate how the power dissipated by a light bulb varies with voltage. To find this out, I will need to do an experiment to test this out and repeat it another two times. Meaning of terms Current - Current is the flow of electric charge. An ammeter measures current in a circuit. Voltage - Voltage is the potential difference between two points in a circuit is the electrical energy gained or lost by 1 coulomb of charge. A voltmeter measures voltage between two points in a circuit. Resistance - If a component has resistance, it changes some of the electrical energy passing through it into another form of energy. A rheostat can increase or decrease its own resistance so in that way I can control the amount of voltage across the light bulb whilst doing the experiment. Prediction I think that as the voltage across a light bulb increases, the power dissipated by the light bulb also increases but at a greater rate. This is because as the voltage increases, the current also increases. This is because if the current is the amount of electrons flowing through a circuit at any point in a circuit and if the voltage increases then the current must increase as the electrons flowing through that point are flowing faster. Therefore, as the voltage increases, the
Graphs illustrating variants of y = sin x.
Part 1 Graph 1 Graph 1 is showing y = sin x. Now lets look at the graphs of y = 2sin x ; y = ? sin x ; y = 5sin x y =2sin x Graph 2 y = 1/3sin x Graph 3 y = 5sin x Graph 4 If we compare graphs 2, 3 and 4 we can see that the number in front of sin (this number is called A) changes the vertical compression of the wave. When A<1 then the graph vertically compresses or amplitude becomes lower (graph 3) and when A>1 then graph expands vertically or amplitude becomes higher (graphs 2 and 4). If the number is 2, then the wave doubles vertically and when the number is 1/2 it compress by half. The comparison is of course made with the graph of sin x. Now let us see what happens when we make the equation negative by putting a minus sign in front of sin. By doing this we are taking A<0. Graph 5 Graph 5 shows us that the wave flips around when A is negative. So we can conclude that when A<0 the wave will always be upside down From investigating graphs of y = Asin x, we can conclude that when the A is less than 1 then the wave compresses vertically and when A is greater than 1 the wave expands vertically. If A is less than 0, then the whole wave flips upside down. To conclude we can say that A will equal to the number on the y-axis because
Investigating factors that affect the bounce height of a squash ball
SC1 Investigation 6/10/06 Investigating factors that affect the bounce height of a squash ball Christopher Lewis Candidate number: 2670 SC1 Investigation Investigating factors that affect the bounce height of a squash ball . Planning ) Investigating factors that affect the bounce height of a squash ball. 2) Background Information I have decided to investigate how the height from which a squash ball is dropped affects the height of its bounce. When a ball is dropped, it accelerates until it collides with the surface - an impact. It then recoils, and some of the energy is reflected back upwards, causing it to bounce. I believe that as the height from which the ball is dropped changes, the speed of the ball at the moment of impact will also change. This is because when the ball is dropped, it accelerates due to the force of gravity. Newton's law states that if the force acting on an object is not zero or the resultant force acting is not zero then the object will accelerate. In this case, the force acting on the object (gravity) is greater than the air resistance, so the object accelerates downwards. Theoretically, when the ball is travelling at a faster speed, there will be more force at the point of impact (due to the increased kinetic energy). Therefore, more potential energy will be stored in the ball as the collisions takes place, which will then be converted
Stars, Supernova and Black holes
Stars, Supernova and Black holes Stars have been around for a long time it starts from a concentration of mass in a cloud of gas and dust this started from a process of collapse. This concentration attracted matter to itself by gravity and the whole cloud started to fall in on itself. As it started to shrink, the cloud began to spin. Gas and dust were pulled in to the centre as they clashed together; it caused the temperature to rise. As the cloud collapsed more and more, it spun faster and faster, as it spinning, it flattened out until a disc formed around a central core to form what is called a solar nebula. Most of the gas and dust from the spinning cloud were released in huge plumes above and below the forming star. The pressure and temperature in the middle of the cloud eventually became so great that the atoms started to fuse releasing huge amounts of energy, and then the star started to shine. The sun is a star, like the other stars it is a ball of very hot gas. The sun gives us huge amounts of energy into space. The energy that keeps the sun shining is produced in its centre or core. The pressure in the core is enormous, and the temperature reaches 15 million degrees centre grade. Under these conditions, atoms of hydrogen gas join together to form another gas called helium. This process is called nuclear fusion. The sun is a very important star in the sky, the sun
length of a simple pendulum affects the time
. Plan Aim To investigate how the length of a simple pendulum affects the time for a complete swing. Variables length The length of the pendulum has a large effect on the time for a complete swing. As the pendulum gets longer the time increases. size of swing Surprisingly, the size of the swing does not have much effect on the time per swing. mass The mass of the pendulum also does not affect the time. air resistance With a small pendulum bob there is very little air resistance. This can easily be seen because it takes a long time for the pendulum to stop swinging, so only a small amount of energy is lost on each swing. A large and light pendulum bob would be affected by a significant amount of air resistance. This might change the way the pendulum moves. gravity The pendulum is moved by the force of gravity pulling on it. On the Moon, where the pull of gravity is less, I would expect the time for each swing to be longer. Theory When the pendulum is at the top of its swing it is momentarily stationary. It has zero kinetic energy and maximum gravitational potential energy. As the pendulum falls the potential energy is transferred to kinetic energy. The speed increases as the pendulum falls and reaches a maximum at the bottom of the swing. Here the speed and kinetic energy are a maximum, and the potential energy is a minimum. As the pendulum rises the
The purpose of this experiment is to see what factors affect the period of one complete oscillation of a simple pendulum.
SCIENCE COURSEWORK PENDULUM EXPERIMENT Aim The purpose of this experiment is to see what factors affect the period of one complete oscillation of a simple pendulum. In this investigation I am going to discover and investigate the factors, which affect the time for one complete oscillation of a simple pendulum. It is important to understand what a pendulum is. A pendulum has a weight or mass fixed and left hanging of the string. An oscillation is one cycle of the pendulums motion e.g. from position a to b and back to a. I will time how long it takes for one oscillation of the pendulum. I am going to do a simple preliminary experiment to investigate which of the factors I test have an effect on the time for one complete oscillation. The factors basic variable factors I can test are: ? Length (the distance between the point of suspension and the mass) ? Mass (the weight in g of the item suspended from the fixed point) ? Swing size (the length I release the pendulum) *The point of equilibrium is the point at which kinetic energy (KE) is the only force making the mass move and not gravitational potential energy (GPE). I will test the extremes of these factors as I can assume that if they have any effect on the period of oscillation it will become obvious. To make sure my results are accurate enough to allow for any anomalies I will repeat the experiment 2 times for each
Ionization energies
INTRODUCTION: The ionization energy of an atom measures how strongly an atom holds its electrons.The ionization energy is the minimum energy required to remove an electron from the ground state of the remote gaseous atom The first ionization energy, I1, is the energy needed to remove the first electron from the atom: i.e. the most loosely held electron! Na(g) -> Na+(g) + 1e- The second ionization energy, I2, is the energy needed to remove the next (i.e. the second) electron from the atom Na+(g) -> Na2+(g) + 1e- The higher the value of the ionization energy, the more difficult it is to remove the electron As electrons are removed, the positive charge from the nucleus remains unchanged, however, there is less repulsion between the remaining electrons INVESTIGATION: Periodic trends in ionization energies First ionization energies as a function of atomic number * 1.Within each period (row) the ionization energy typically increases with atomic number * 2.Within each group (column) the ionization energy typically decreases with increasing atomic number HYPOTHESIS: * Investigation 1: As the effective charge increases, or as the distance of the electron from the nucleus decreases, the greater the attraction between the nucleus and the electron. The effective charge increases across a period, in addition, the atomic radius decreases * Investigation 2: As we move
