Are mobile phones dangerous? Research Project.
Are Mobile Phones Dangerous? Introduction I am looking at ‘Are mobile phones dangerous?’ The case study has some relevance to the current news topics because the findings have been made public and people are always asking ‘are there any risks’, as you will find out there are many theories and supposed evidence, that may or may not be reliable. In this study I will be looking for a correlation between mobile phone usage and fertility in men, increased risk of brain tumours and other negative side effects such as concentration levels. Background information: (information from http://www.vodafone.com.au/personal/aboutvodafone/healthmobilephonetechnology/howdoesthemobilephonesystemwork/index.htm ) Mobile phones use radio waves however some have a higher frequency so can be classed as microwaves. Radio waves are used for communication. Long wave radio has lengths of about 1km. Mobile telephones are two-way radios. When you talk into a mobile telephone, it picks up your voice and converts the sound to radiofrequency energy (or radio waves). The radio waves travel through the air until they reach a receiver at a nearby base station. The base station then sends your call through the telephone network until it reaches the person you are calling. When you receive a call on
The Fundamentals of Radio Wave Propagation
The Fundamentals of Radio Wave Propagation How do radio waves get from one location to another? Why does a signal at generated at Point A, which is several thousand miles away, reach Point B without a complicated myriad of connecting wires? The answer, in three words, is radio wave propagation. Radio wave propagation theory is of particular importance to wireless communications, for, without a preliminary understanding of the physical nature of wave propagation it is impossible to ensure that communications can be established at all. * Transmission and Reception In a wireless environment radio frequencies are transmitted outward from a source, which is usually an antenna. Antennas provide the link between the grounded and free-space parts of a communications system. The transmitting antenna is charged with the task of transforming the electrical signal into electromagnetic radiant energy, the purpose of the receiving antennae is to accept the received radiated energy and efficiently convert it into an electrical signal for processing by the receiver. The portion of the electromagnetic spectrum that constitutes radio waves ranges from about 30 kHz to 300 GHz. (Fig. 1) Frequency Name Frequency Range Wavelength Low Frequency 0-300 kHz 30-1 km Medium Frequency (mf) 300-3000kHz 000-100m High Frequency (hf) 3-30 MHz 00-10m Very High Frequency (VHF) 30-300MHz 0-1m
Physics of Music - How a guitar works.
Physics of Music How a guitar works A typical guitar has six strings. These are all of the same length, and all under about the same tension, so why do they put out sound of different frequency? If you look at the different strings, they're of different sizes, so the mass/length of all the strings is different. The one at the bottom has the smallest mass/length, so it has the highest frequency. The strings increase in mass/length as you move up, so the top string, the heaviest, has the lowest frequency. Tuning a guitar simply means setting the fundamental frequency of each string to the correct value. This is done by adjusting the tension in each string. If the tension is increased, the fundamental frequency increases; if the tension is reduced the frequency will decrease. To obtain different notes (i.e., different frequencies) from a string, the string's length is changed by pressing the string down until it touches a fret. This shortens a string, and the frequency will be increased. Wind instruments and longitudinal standing waves Pipes work in a similar way as strings, so we can analyze everything from organ pipes to flutes to trumpets. The big difference between pipes and strings is that while we consider strings to be fixed at both ends, the tube is either free at both ends (if it is open at both ends) or is free at one end and fixed at the other (if the tube is
SIGNAL ANALYSIS
Engineering Lab Report AIMS 2 OBJECTIVES 2 PART 1: 2 PART 2: 2 EQUIPMENT 2 PROCEDURE 3 PART 1: 3 THEORY 4 FILTERS: 4 Fig 1 Ideal Filter 4 Fig 2 Typical Filter 5 Fig 3 Typical 2-stage Filter 5 TRANSFER FUNCTIONS AND THE LAPLACE TRANSFORM: 6 FOURIER ANALYSIS: 8 Components of a sine function: 8 RESULTS 9 LOW PASS FILTER 9 Table of Results: 9 Graph of Results: 9 Bode Plot for the Low Pass Filter: 10 HIGH PASS FILTER 10 Table of Results: 10 Graph of Results: 11 Bode Plot for the High Pass Filter: 11 BAND PASS FILTER 12 Table of Results: 12 Graph of Results: 13 Bode Plot for the Band Pass Filter: 13 STOP BAND FILTER 14 Table of Results: 14 Graph of Results: 15 Bode Plot for the Band Stop Filter: 15 2-STAGE LOW PASS FILTER 16 Table of Results: 16 Graph of Results: 16 Bode Plot for the 2-StageLow Pass Filter: 17 RESULTS FOR PART 2 17 SQUARE WAVE: 17 RAMP FUNCTION: 18 HALF WAVE RECTIFIER: 20 FULL WAVE RECTIFIER: 20 MODULATED SINE WAVE: 21 MODULATED SQUARE WAVE 21 DISCUSSION 22 CONCLUSION 23 APPENDICES 24 SIGNAL ANALYSIS AIMS Through experimentation of signal analysis, an understanding will be gained of a signal's behaviour when passing through filter systems of various orders. This also includes the understanding of the mathematical representation of signals and filter systems in both time and frequency domains with the use of Fourier
'Investigate the factors which affect the strength of an electromagnet'
Henal Rajendra Patel CENTRE NUMBER: 14625 CANDIDATE NUMBER: 0127 'Investigate the factors which affect the strength of an electromagnet' An electromagnet can also be called a solenoid. An electromagnet can consist of just one wire, but usually an electromagnet is made up of wire coiled around a soft ferromagnetic core. TASK & AIM: An electromagnet can be used to pick up objects. I will choose a factor which will affect the strength of an electromagnet I have made and investigate how it affects the strength of your electromagnet. THE FACTORS THAT AFFECT THE STRENGTH OF AN ELECTROMAGNET: * Amount of Current * Length of the core * Diameter * Thickness of the wire used for the coils * Type of core * Number of turns on the electromagnet I will vary the number of turns on the electromagnet as that is the factor I have chosen to study, and I will keep the other factors constant. I feel that the more turns that I have on the electromagnet the more iron filings will be picked up. I chose to investigate this factor because I thought that this factor would give me the most reliable results. The current I will keep constant at 0.2 amps, the thickness of the wire I have used for the coils will stay the same for both experiments. The coils of wire will be tied round at the same strength for both experiments. Henal Rajendra Patel CENTRE NUMBER: 14625 CANDIDATE NUMBER:
Properties of waves
Properties of waves I. What is a wave A wave is a disturbance that carries energy through matter or space. II. Most waves travel through a medium i. sound travels as a wave a. the air through which sound travels is its medium ii. earth quakes make waves called seismic waves that travel through earth a. medium- the matter through which a wave travels b. waves that require a medium to travel through are called mechanical waves . almost all waves are mechanical waves 2. an exception to this is electromagnetic waves III. Light does not require a medium i. light can travel from the sun to the earth across the empty space ii. this is possible because light waves do not need a medium to t ravel through iii. light waves consist of changing electric and magnetic fields in space a. electromagnetic waves- a wave caused by a disturbance in electric and magnetic fields and that does not require a medium IV. Waves transfer energy i. waves carry energy because they can do work. ii. Ii. The bigger the wave is, the more energy it carries a. A cruise ship moving through water in the ocean could create waves big enough to move a fishing boat up and down a few meters. iii. Tsunami- a huge ocean wave caused by earthquakes a. A tsunami may be as high as 30 meters when it reaches the shore . such waves carry enough energy to cause a lot of damage to costal
Convection - What it is and how it works
Convection What it is and how it works Convection of heat occurs when the atoms in a liquid or a gas move away from there neighbouring atoms. This causes the local area expand and consequently become less dense than the surrounding fluid. Convection works by something heating up and becoming less dense than the surroundings. The less dense object will rise due to buoyant forces. When the less dense object cools down it will become denser and return to its original position. The two types of convection Convection comes in two types natural and forced. Heated air rising is an example of natural convection. Forced convection is when a pump or a mechanism moves the heated fluid. Some examples of forced convection are some types of ovens, refrigerators and air conditioners. Lava Lamp A lava lamp is an example of convection the heater in the base of the lamp heat up the fake lava. Due to the rapidly increased temp the lava expands making it less dense than the surrounding liquid. The less dense lava then floats to the top. When it is at the top it starts to get smaller and less dense than the surrounding liquid. This means it then floats down to the bottom again. Radiator In most houses we have a radiator. The heat given of by them is mainly produced by convection. The convector heater warms the air in contact with it this then becomes less dense and rises. The
To investigate the resonant frequency of the fundamental mode of vibration of air in a container
Physics Planning Exercise Introduction This experiment is designed to investigate the resonant frequency of the fundamental mode of vibration of air in a container depends on the volume of air within the container. A standing wave (or stationary wave) is produced at the resonant frequency and a node and an anti-node are produced from this where the node is the point at which the wave never moves at all, and the anti-node is the place at which the wave can move about freely. The fundamental mode is the simplest standing/stationary wave that can be produced. Resonance is the condition in which an acoustic system vibrates in response to a force applied to the system's natural frequency. The natural frequency is that at which the system would vibrate if deflected once and then allowed to move freely. If a system is excited by the continued application of external forces at this frequency the amplitude of the oscillation will build up and may lead the destruction of the device or structure. Procedure This experiment can be investigated by using a resonance tube, and a set of tuning forks. The volume of air in the tube can be changed by moving the inner tube up and down. The width of the inner tube will not change throughout the whole experiment- making it a fair test. Also different tuning forks can be used to give a varied range of frequencies so that I see how the
Describe and explain how a simple radio receiver and transceiver works and then explain one of its uses in an ILS (Instrument Landing System).
Physics Coursework 2003 ILS (Instrument Landing System) Chris Tootell 0743 (HN) 51113 Contents Contents 2 Introduction: 3 Description: 3 Background: 3 How Does It Work? 4 UHF and VHF Equipment: 4 The Aerials: 5 The Localiser Transmitter: 5 Glide Path Transmitter: 6 Autoland Capabilities: 8 Problems Of The ILS: 8 Bibliography: 9 Introduction: In this reading and research project I am going to describe and explain how a simple radio receiver and transceiver works and then explain one of its uses in an ILS (Instrument Landing System). I am then going to go on and explain its application and importance around the world in everyday usage. In the description the main three sections involved in how the ILS works will be covered as well as the background to the use of the ILS and the uses of it. Description: Now I have covered the way in which radio waves are transmitted and received and the construction of the devices needed I am going to move onto the application of there use. I am going to use an ILS as the use of radio and will describe how it works. ILS is short for Instrument Landing System. The ILS is basically a pilot interpreted runway approach aid. This means that it will 'help' the pilot of an aircraft fitted with ILS equipment to make an approach to an airport that is equipped with ILS transmitting equipment. Although it sounds very simple a design
