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A level Physics assignment-'Waves'.
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This MRI scan shows the upper torso in side view so that the bones of the spine are evident.
I.R. and U.V waves, skin treatments, type of U.V.light used and how it is produced: Infra red waves have a very short length, although longer than visible light. Beyond the red end of the visible spectrum, is infra red and it is just below visible red light in the electromagnetic spectrum ("Infra" means "below"). We can see the red light, and feel the warmth on our skin. Infra-red waves are used for many tasks, for example, TV remote controls and video recorders. Because every object gives off IR waves, we can use them to "see in the dark". Night sites for weapons sometimes use a sensitive IR detector. They are used in medicine too: physiotherapists use heat lamps to help heal sports injuries and infra red pictures may reveal tumours. By combining infra-red and computer technologies, we are able to produce thermograms (heat pictures) having up to 256 colours which clearly show thermal profiles and temperature measurements. In this way we are able to detect areas that may need medical attention as they will show a change of blood flow and can therefore be easily detected. Plus the procedure is totally non - invasive and does not involve ionizing radiation. It is without patient risk.
Ultra violet lights have very high energy and very short wave lengths; shorter than visible light. Some animals like honey bees can see ultra-violet light. Some plants have white flowers, at least you think that they are all white, but they may appear to be different colours to a honey bee because of the amounts of ultra-violet light which they reflect. Ultra-violet light is produced by exciting atoms that then emit a photon at the right energy level. However, there is no attempt to cause massive secondary emission or to make the light coherent. Though UV light does cause a heating effect – sunlight contains a certain amount of UV, which is what causes sunburn, skin aging, cancer and the like – it is also absorbed by certain pigments in layers just under the skin. The energy thus absorbed is used to power chemical reactions that make certain important vitamins that accelerate skin healing.
UV waves are divided into three categories, UV-A 400nm-315nm: Often referred to as 'blacklight', this is the longest wavelength region and lowest energy; it represents the largest portion of natural UV light. UV-B 315nm-280nm: Partially blocked by the ozone layer this is the most aggressive component of natural UV light and largely responsible for sunburn (erythema). UV-C 280nm-100nm: Only generally encountered from artificial light sources since it is totally absorbed by the earth's atmosphere. From treating vitamin D deficiencies and relieving the unsightly effects of Psoriasis and various other skin conditions, UV-A and UV-B light is used in many treatments and research projects in the world of medicine. Latest medical breakthroughs include fluorescent dyes used in conjunction with blacklight to identify cancerous cells in the internal organs of patients.
Visible light, laser treatments, endoscopy: Our eyes can detect only a tiny part of the electromagnetic spectrum, called ‘visible light’. This means that there's a great deal happening around us that we're simply not aware of, unless we have instruments to detect it. Light waves are given off by anything that's hot enough to glow.
This is how light bulbs work - an electric current heats the lamp filament to around 3,000 degrees, and it glows white-hot. White light is actually made up of a whole range of colours, mixed together.
With laser light all the crests and troughs line up with each other. Which means that all the light is exactly the same colour. This is called "monochromatic". Also, all the waves are going in the same direction. It is much more "orderly" than the other light. We can also think of light as little particles. With a laser these particles come in a perfectly uniform stream all going in the same direction. Because it is so orderly we can control laser light extremely well. We know that if light of the right colour hits an atom, it will bump an electron up to a higher energy level and later the electron falls back down, giving off light of the same colour in some random direction. However, if the "brightness" of the light source, which makes the particles of light called photons, come out faster there is a significant change. When a photon hits an atom that is already excited, the atom lets go of the photon and it ends up going in the same direction as the incoming photon. When a photon hits an atom that is already excited, the atom releases a new photon that is completely identical to the incoming photon; same colour, going in the same direction. This is called "stimulated emission".
When one photon hits an excited atom there are two photons travelling together. When one of those finds another excited atom, there are three photons, and so on and so on, but they are all exactly the same because they are being cloned by stimulated emission. The number of photons gets amplified. The word laser is short for "light amplification by stimulated emission of radiation". So the incoming light is a wave, and when it hits the excited atom, the atom releases some energy that just makes the wave get bigger.
However, in order to excite the atom, it needs to be hit with a photon to start with. It takes two photons to get two photons; but by exciting a number of atoms simultaneously, without hitting them with protons, a chain reaction can be created. This is called Population Inversion. This is done by pumping electrical energy into the atoms in certain ways or shining different coloured light at them. Both these processes stick the atoms into much higher energy levels and under special conditions then they jump down and accumulate in the one excited energy level instead of going all the way to the ground state.
When an excited atom sends off a photon, it can hit more excited atoms and cause a little landslide of more photons; but the photons can go off in any direction. So mirrors are used to bounce the photons back and forth along one direction through the atoms and a partially reflective mirror is used on one end so that some of the light leaks through. The beam inside the laser is a lot more powerful than the beam that actually comes out. A laser beam contains a lot of synchronised energy. Instead of being randomised, like ordinary light, all the photons march together. Imagine a lot of people marching together across a wobbly rope bridge. Their synchronised stamping would quickly cause the bridge to resonate and it would probably break. The same sort of thing happens with the laser hitting a material. The photons cause a local heating effect that “burns” the material, breaking molecules apart. If you have ever focussed the light of the sun onto something and seen it burn then you has seen the same effect. Because it is so coherent, laser beams can be focussed with great precision and so the cutting can be very precise.
Laser treatment can be used for cosmetic surgery (tattoo, scar, stretch mark, sunspot, wrinkle, birthmark and hair removal; eye surgery; laser scalpel (gynecological, urology, laparoscopic); dental procedures; imaging and "No-Touch" removal of tumors, especially of the brain and spinal cord. The main effects of laser treatment are that it inhibits inflammation, promotes circulation and it is an analgesic.
Endoscopes: An optical fibre is like a “tunnel” with extremely reflective walls. Photons rush down the tunnel with no way out and because only a few can get in at a time, they don’t interfere with each other (very much). By packing a bundle of these fibres together (several hundreds, if not thousands), each can transmit part of an image back to either a microscope or a digital camera to be magnified. Note that some of the fibres can be used to carry illumination down to the far end, too. The fibres used in an endoscope are generally made either from glass or from a special kind of plastic that can be extruded very, very thin – only a few millionths of a meter in diameter. At that thickness, glass becomes surprisingly flexible. Therefore endoscopes can be used to travel inside the body and gather information. An endoscopy is the medical term for such a procedure. So an endoscope is an instrument to visualize the inner surface of a hollow object via a small entrance hole. The object can be the human body, animal body or mechanical body. The type of endoscope depends on the focus of the examination through natural and artificial openings. Medical endoscopes are divided into categories such as gastro-intestinal instruments (Gastroscope; colonoscope; sigmoidoscope), airway instruments (bronchoscope; nasopharyngoscope), urological instruments and miscellaneous instruments.
I.R. and U.V waves, skin treatments, type of U.V.light used and how it is produced: Infra red waves have a very short length, although longer than visible light. Beyond the red end of the visible spectrum, is infra red and it is just below visible red light in the electromagnetic spectrum ("Infra" means "below"). We can see the red light, and feel the warmth on our skin. Infra-red waves are used for many tasks, for example, TV remote controls and video recorders. Because every object gives off IR waves, we can use them to "see in the dark". Night sites for weapons sometimes use a sensitive IR detector. They are used in medicine too: physiotherapists use heat lamps to help heal sports injuries and infra red pictures may reveal tumours. By combining infra-red and computer technologies, we are able to produce thermograms (heat pictures) having up to 256 colours which clearly show thermal profiles and temperature measurements. In this way we are able to detect areas that may need medical attention as they will show a change of blood flow and can therefore be easily detected. Plus the procedure is totally non - invasive and does not involve ionizing radiation. It is without patient risk.
Ultra violet lights have very high energy and very short wave lengths; shorter than visible light. Some animals like honey bees can see ultra-violet light. Some plants have white flowers, at least you think that they are all white, but they may appear to be different colours to a honey bee because of the amounts of ultra-violet light which they reflect. Ultra-violet light is produced by exciting atoms that then emit a photon at the right energy level. However, there is no attempt to cause massive secondary emission or to make the light coherent. Though UV light does cause a heating effect – sunlight contains a certain amount of UV, which is what causes sunburn, skin aging, cancer and the like – it is also absorbed by certain pigments in layers just under the skin. The energy thus absorbed is used to power chemical reactions that make certain important vitamins that accelerate skin healing.
UV waves are divided into three categories, UV-A 400nm-315nm: Often referred to as 'blacklight', this is the longest wavelength region and lowest energy; it represents the largest portion of natural UV light. UV-B 315nm-280nm: Partially blocked by the ozone layer this is the most aggressive component of natural UV light and largely responsible for sunburn (erythema). UV-C 280nm-100nm: Only generally encountered from artificial light sources since it is totally absorbed by the earth's atmosphere. From treating vitamin D deficiencies and relieving the unsightly effects of Psoriasis and various other skin conditions, UV-A and UV-B light is used in many treatments and research projects in the world of medicine. Latest medical breakthroughs include fluorescent dyes used in conjunction with blacklight to identify cancerous cells in the internal organs of patients.
Visible light, laser treatments, endoscopy: Our eyes can detect only a tiny part of the electromagnetic spectrum, called ‘visible light’. This means that there's a great deal happening around us that we're simply not aware of, unless we have instruments to detect it. Light waves are given off by anything that's hot enough to glow.
This is how light bulbs work - an electric current heats the lamp filament to around 3,000 degrees, and it glows white-hot. White light is actually made up of a whole range of colours, mixed together.
With laser light all the crests and troughs line up with each other. Which means that all the light is exactly the same colour. This is called "monochromatic". Also, all the waves are going in the same direction. It is much more "orderly" than the other light. We can also think of light as little particles. With a laser these particles come in a perfectly uniform stream all going in the same direction. Because it is so orderly we can control laser light extremely well. We know that if light of the right colour hits an atom, it will bump an electron up to a higher energy level and later the electron falls back down, giving off light of the same colour in some random direction. However, if the "brightness" of the light source, which makes the particles of light called photons, come out faster there is a significant change. When a photon hits an atom that is already excited, the atom lets go of the photon and it ends up going in the same direction as the incoming photon. When a photon hits an atom that is already excited, the atom releases a new photon that is completely identical to the incoming photon; same colour, going in the same direction. This is called "stimulated emission".
When one photon hits an excited atom there are two photons travelling together. When one of those finds another excited atom, there are three photons, and so on and so on, but they are all exactly the same because they are being cloned by stimulated emission. The number of photons gets amplified. The word laser is short for "light amplification by stimulated emission of radiation". So the incoming light is a wave, and when it hits the excited atom, the atom releases some energy that just makes the wave get bigger.
However, in order to excite the atom, it needs to be hit with a photon to start with. It takes two photons to get two photons; but by exciting a number of atoms simultaneously, without hitting them with protons, a chain reaction can be created. This is called Population Inversion. This is done by pumping electrical energy into the atoms in certain ways or shining different coloured light at them. Both these processes stick the atoms into much higher energy levels and under special conditions then they jump down and accumulate in the one excited energy level instead of going all the way to the ground state.
When an excited atom sends off a photon, it can hit more excited atoms and cause a little landslide of more photons; but the photons can go off in any direction. So mirrors are used to bounce the photons back and forth along one direction through the atoms and a partially reflective mirror is used on one end so that some of the light leaks through. The beam inside the laser is a lot more powerful than the beam that actually comes out. A laser beam contains a lot of synchronised energy. Instead of being randomised, like ordinary light, all the photons march together. Imagine a lot of people marching together across a wobbly rope bridge. Their synchronised stamping would quickly cause the bridge to resonate and it would probably break. The same sort of thing happens with the laser hitting a material. The photons cause a local heating effect that “burns” the material, breaking molecules apart. If you have ever focussed the light of the sun onto something and seen it burn then you has seen the same effect. Because it is so coherent, laser beams can be focussed with great precision and so the cutting can be very precise.
Laser treatment can be used for cosmetic surgery (tattoo, scar, stretch mark, sunspot, wrinkle, birthmark and hair removal; eye surgery; laser scalpel (gynecological, urology, laparoscopic); dental procedures; imaging and "No-Touch" removal of tumors, especially of the brain and spinal cord. The main effects of laser treatment are that it inhibits inflammation, promotes circulation and it is an analgesic.
Endoscopes: An optical fibre is like a “tunnel” with extremely reflective walls. Photons rush down the tunnel with no way out and because only a few can get in at a time, they don’t interfere with each other (very much). By packing a bundle of these fibres together (several hundreds, if not thousands), each can transmit part of an image back to either a microscope or a digital camera to be magnified. Note that some of the fibres can be used to carry illumination down to the far end, too. The fibres used in an endoscope are generally made either from glass or from a special kind of plastic that can be extruded very, very thin – only a few millionths of a meter in diameter. At that thickness, glass becomes surprisingly flexible. Therefore endoscopes can be used to travel inside the body and gather information. An endoscopy is the medical term for such a procedure. So an endoscope is an instrument to visualize the inner surface of a hollow object via a small entrance hole. The object can be the human body, animal body or mechanical body. The type of endoscope depends on the focus of the examination through natural and artificial openings. Medical endoscopes are divided into categories such as gastro-intestinal instruments (Gastroscope; colonoscope; sigmoidoscope), airway instruments (bronchoscope; nasopharyngoscope), urological instruments and miscellaneous instruments.
Xray – CT/CAT Scans: These rays are, like light and radio waves, a form of electromagnetic radiation. X-rays have high energy and short wavelength and are able to pass through tissue. On their passage through the body, the denser tissues, such as the bones, will block more of the rays than will the less dense tissues, such as the lung.
A special type of photographic film is used to record X-ray pictures. The X-rays are converted into light and the more energy that has reached the recording system, the darker that region of the film will be. This is why the bones on an X-ray image appear whiter (less energy passes through) than the lungs (more energy passes through). A simple X-ray image can be extremely informative. For example it can show whether or not a bone is broken or whether or not there is a shadow on the lung.
Special X-ray techniques can also be used to investigate other problems with the soft tissues of the body. By injecting special dye into arteries and/or veins the blood vessels can be made visible. By swallowing special dye the gullet and stomach can be examined. Similar dye can be introduced via an enema to examine the back passage and the rest of the large bowel
X-rays are just very high energy photons – they are another form of light energy. However, they are well beyond the range of visible light. When they hit certain materials – particularly mica – they cause the atoms of that material to jump up to a very high energy level – skipping several intermediate levels. As these electrons “fall” back into more stable orbits, they emit photons of lower energy than the X-ray. Some of these can be in the visible range and will be seen as a little flash of light – a “scintillation”. These can be seen under a microscope or detected with a digital camera. X-Rays have so much energy and such a short wavelength that they can go right through you. However, they cannot get through bone as easily as they can get through muscle. This is because your bones contain so much Calcium. X-Ray can also be used to find other problems in your body. If the doctors want to look for ulcers in your guts, they can give you a Barium meal. Like Calcium, the Barium absorbs X-Rays so the doctors can look at parts of your guts and find your ulcers.
The heart of an X-ray machine is an electrode pair -- a cathode and an anode -- that sits inside a glass vacuum tube. The cathode is a heated filament, like you might find in an older fluorescent lamp. The machine passes current through the filament, heating it up. The heat sputters electrons off of the filament surface. The positively-charged anode, a flat disc made of tungsten, draws the electrons across the tube. The voltage difference between the cathode and anode is extremely high, so the electrons fly through the tube with a great deal of force. When a speeding electron collides with a tungsten atom, it knocks loose an electron in one of the atom's lower orbitals. An electron in a higher orbital immediately falls to the lower energy level, releasing its extra energy in the form of a photon. It's a big drop, so the photon has a high energy level -- it is an X-ray photo Free electrons can also generate photons without hitting an atom. An atom's nucleus may attract a speeding electron just enough to alter its course. Like a comet whipping around the sun, the electron slows down and changes direction as it speeds past the atom. This "braking" action causes the electron to emit excess energy in the form of an X-ray photon.
The high-impact collisions involved in X-ray production generate a lot of heat. A motor rotates the anode to keep it from melting (the electron beam isn't always focused on the same area). A cool oil bath surrounding the envelope also absorbs heat.
The entire mechanism is surrounded by a thick lead shield. This keeps the X-rays from escaping in all directions. A small window in the shield lets some of the X-ray photons escape in a narrow beam. The beam passes through a series of filters on its way to the patient. A camera on the other side of the patient records the pattern of X-ray light that passes all the way through the patient's body. The X-ray camera uses the same film technology as an ordinary camera, but X-ray light sets off the chemical reaction instead of visible light.
A CT (computerised tomography) scanner is a special kind of X-ray machine. Instead of sending out a single X-ray through your body as with ordinary X-rays, several beams are sent simultaneously from different angles. The X-rays from the beams are detected after they have passed through the body and their strength is measured. Beams that have passed through less dense tissue such as the lungs will be stronger, whereas beams that have passed through denser tissue such as bone will be weaker. A computer can use this information to work out the relative density of the tissues examined. Each set of measurements made by the scanner is, in effect, a cross-section through the body. The computer processes the results, displaying them as a two-dimensional picture shown on a monitor. CT scans are far more detailed than ordinary X-rays. The information from the two-dimensional computer images can be reconstructed to produce three-dimensional images by some modern CT scanners. They can be used to produce virtual images that show what a surgeon would see during an operation. CT scans have already allowed doctors to inspect the inside of the body without having to operate or perform unpleasant examinations. CT scanning has also proven invaluable in pinpointing tumours and planning treatment with radiotherapy.
Y-ray – Y Camera – Radiotherapy: A form of electromagnetic radiation, similar to X-rays but of shorter wavelength. Y-rays and X-rays are also used therapeutically to kill tumour cells. Radiotherapy is the use of Y rays to treat disease. It used to be known as radium treatment although very little radium is used these days. Although radiotherapy uses stronger rays than those used for taking pictures it feels no different and is painless. Approximately four out of ten people with cancer will have radiotherapy as part of their treatment. This can either be given from outside the body (external radiotherapy), using a Y- ray camera or cobalt irradiation, or from within (internal radiotherapy), by placing radioactive treatment in or close to the tumour being treated. The Y rays work by destroying the cancer cells in the treated area. Although normal cells are also affected, they can repair themselves. Y-rays are like X-rays but of higher energy. Same principles but they cause more damage.
Cancerous cells are destroyed in radiotherapy by burning them. Three separate beams are usually focussed through the body from different angles. Each beam by itself can not cause too much damage but where all three meet (inside the cancer) the combined burning effect kills the cancer cells. Radiotherapy kills all cells in the target area at about a 30% rate of attrition. Cancer cells are simply normal healthy cells that don't go on to differentiate - either partially or fully - they simply duplicate. Therefore, almost as soon as they come into being, they duplicate again. New cells can become anything. Differentiation means to further develop function according to the immediate environment (new cells in a hair become hair-cells, in a kidney, kidney cells, etc.) This takes much more time, before they can again duplicate. At the moment of cell division, they are the most vulnerable. Therefore, radiotherapy administered over time finally kills more undifferentiated (cancer) cells than it does those that are differentiated.
A special type of photographic film is used to record X-ray pictures. The X-rays are converted into light and the more energy that has reached the recording system, the darker that region of the film will be. This is why the bones on an X-ray image appear whiter (less energy passes through) than the lungs (more energy passes through). A simple X-ray image can be extremely informative. For example it can show whether or not a bone is broken or whether or not there is a shadow on the lung.
Special X-ray techniques can also be used to investigate other problems with the soft tissues of the body. By injecting special dye into arteries and/or veins the blood vessels can be made visible. By swallowing special dye the gullet and stomach can be examined. Similar dye can be introduced via an enema to examine the back passage and the rest of the large bowel
X-rays are just very high energy photons – they are another form of light energy. However, they are well beyond the range of visible light. When they hit certain materials – particularly mica – they cause the atoms of that material to jump up to a very high energy level – skipping several intermediate levels. As these electrons “fall” back into more stable orbits, they emit photons of lower energy than the X-ray. Some of these can be in the visible range and will be seen as a little flash of light – a “scintillation”. These can be seen under a microscope or detected with a digital camera. X-Rays have so much energy and such a short wavelength that they can go right through you. However, they cannot get through bone as easily as they can get through muscle. This is because your bones contain so much Calcium. X-Ray can also be used to find other problems in your body. If the doctors want to look for ulcers in your guts, they can give you a Barium meal. Like Calcium, the Barium absorbs X-Rays so the doctors can look at parts of your guts and find your ulcers.
The heart of an X-ray machine is an electrode pair -- a cathode and an anode -- that sits inside a glass vacuum tube. The cathode is a heated filament, like you might find in an older fluorescent lamp. The machine passes current through the filament, heating it up. The heat sputters electrons off of the filament surface. The positively-charged anode, a flat disc made of tungsten, draws the electrons across the tube. The voltage difference between the cathode and anode is extremely high, so the electrons fly through the tube with a great deal of force. When a speeding electron collides with a tungsten atom, it knocks loose an electron in one of the atom's lower orbitals. An electron in a higher orbital immediately falls to the lower energy level, releasing its extra energy in the form of a photon. It's a big drop, so the photon has a high energy level -- it is an X-ray photo Free electrons can also generate photons without hitting an atom. An atom's nucleus may attract a speeding electron just enough to alter its course. Like a comet whipping around the sun, the electron slows down and changes direction as it speeds past the atom. This "braking" action causes the electron to emit excess energy in the form of an X-ray photon.
The high-impact collisions involved in X-ray production generate a lot of heat. A motor rotates the anode to keep it from melting (the electron beam isn't always focused on the same area). A cool oil bath surrounding the envelope also absorbs heat.
The entire mechanism is surrounded by a thick lead shield. This keeps the X-rays from escaping in all directions. A small window in the shield lets some of the X-ray photons escape in a narrow beam. The beam passes through a series of filters on its way to the patient. A camera on the other side of the patient records the pattern of X-ray light that passes all the way through the patient's body. The X-ray camera uses the same film technology as an ordinary camera, but X-ray light sets off the chemical reaction instead of visible light.
A CT (computerised tomography) scanner is a special kind of X-ray machine. Instead of sending out a single X-ray through your body as with ordinary X-rays, several beams are sent simultaneously from different angles. The X-rays from the beams are detected after they have passed through the body and their strength is measured. Beams that have passed through less dense tissue such as the lungs will be stronger, whereas beams that have passed through denser tissue such as bone will be weaker. A computer can use this information to work out the relative density of the tissues examined. Each set of measurements made by the scanner is, in effect, a cross-section through the body. The computer processes the results, displaying them as a two-dimensional picture shown on a monitor. CT scans are far more detailed than ordinary X-rays. The information from the two-dimensional computer images can be reconstructed to produce three-dimensional images by some modern CT scanners. They can be used to produce virtual images that show what a surgeon would see during an operation. CT scans have already allowed doctors to inspect the inside of the body without having to operate or perform unpleasant examinations. CT scanning has also proven invaluable in pinpointing tumours and planning treatment with radiotherapy.
Y-ray – Y Camera – Radiotherapy: A form of electromagnetic radiation, similar to X-rays but of shorter wavelength. Y-rays and X-rays are also used therapeutically to kill tumour cells. Radiotherapy is the use of Y rays to treat disease. It used to be known as radium treatment although very little radium is used these days. Although radiotherapy uses stronger rays than those used for taking pictures it feels no different and is painless. Approximately four out of ten people with cancer will have radiotherapy as part of their treatment. This can either be given from outside the body (external radiotherapy), using a Y- ray camera or cobalt irradiation, or from within (internal radiotherapy), by placing radioactive treatment in or close to the tumour being treated. The Y rays work by destroying the cancer cells in the treated area. Although normal cells are also affected, they can repair themselves. Y-rays are like X-rays but of higher energy. Same principles but they cause more damage.
Cancerous cells are destroyed in radiotherapy by burning them. Three separate beams are usually focussed through the body from different angles. Each beam by itself can not cause too much damage but where all three meet (inside the cancer) the combined burning effect kills the cancer cells. Radiotherapy kills all cells in the target area at about a 30% rate of attrition. Cancer cells are simply normal healthy cells that don't go on to differentiate - either partially or fully - they simply duplicate. Therefore, almost as soon as they come into being, they duplicate again. New cells can become anything. Differentiation means to further develop function according to the immediate environment (new cells in a hair become hair-cells, in a kidney, kidney cells, etc.) This takes much more time, before they can again duplicate. At the moment of cell division, they are the most vulnerable. Therefore, radiotherapy administered over time finally kills more undifferentiated (cancer) cells than it does those that are differentiated.
If no-one looks at it for you in the meantime I will try and have a look at it tomorrow for you 
Its too late at night to think straight now
Its too late at night to think straight now I used the first piece as notes for the second and am about to start again using both lots as notes.
3rd time lucky eh.
The bit that foxes me is the 'write it like an A level student'-only because although I can see that there is plenty of room for ctiticism within the work I have produced-it is hard to imagine that I have completed all my other work to that standard and seem to be having so much difficulty with this......and what's more-I really like physics!!I guess I need to make it as objective as possible and only include what is neccessary.
Obviously there are diagrams throughout that aren't showing on here>>>>
Wodaufink?
3rd time lucky eh.
The bit that foxes me is the 'write it like an A level student'-only because although I can see that there is plenty of room for ctiticism within the work I have produced-it is hard to imagine that I have completed all my other work to that standard and seem to be having so much difficulty with this......and what's more-I really like physics!!I guess I need to make it as objective as possible and only include what is neccessary.
Obviously there are diagrams throughout that aren't showing on here>>>>
Wodaufink?
Man!! I tell you-this assignment is driving me mad and the teacher that gave it in the first place even more!!!!!
Anyone-read my attempts and tell me where I am going wrong?
I swear to you that he has put every obstacle there that he can including holding onto it all these months so I barely have the time to do it anyway!
Please-just take a look at what I have posted if you will-and tell me what you think?
Anyone-read my attempts and tell me where I am going wrong?
I swear to you that he has put every obstacle there that he can including holding onto it all these months so I barely have the time to do it anyway!
Please-just take a look at what I have posted if you will-and tell me what you think?
sazzarooo
Man!! I tell you-this assignment is driving me mad and the teacher that gave it in the first place even more!!!!!
Anyone-read my attempts and tell me where I am going wrong?
I swear to you that he has put every obstacle there that he can including holding onto it all these months so I barely have the time to do it anyway!
Please-just take a look at what I have posted if you will-and tell me what you think?
Anyone-read my attempts and tell me where I am going wrong?
I swear to you that he has put every obstacle there that he can including holding onto it all these months so I barely have the time to do it anyway!
Please-just take a look at what I have posted if you will-and tell me what you think?
Right... you owe me big time. I just spent an hour going through that
. Overall very good. You show good understanding & you use a good vocabulary. Ive marked changes or suggestions in pink. Up to you whether you use them. Ive attached it as a word document I think. If you cant see it PM me your email address & I'll send it that way.I really hope it helps
Good luck Cheers for that. I have sent you an email in response to yours-but just to say a big thankyou for giving it the attention you have. I am on my way now. May have a couple more questions but I will try to progress smoothly now.
Thanks again-let me know what I can do for you.......
Have you checked out my blog?
but I will try to progress smoothly now.Thanks again-let me know what I can do for you.......
Have you checked out my blog?
sazzarooo
Cheers for that. I have sent you an email in response to yours-but just to say a big thankyou for giving it the attention you have. I am on my way now. May have a couple more questions but I will try to progress smoothly now.
Thanks again-let me know what I can do for you.......
Have you checked out my blog?
but I will try to progress smoothly now.Thanks again-let me know what I can do for you.......
Have you checked out my blog?
By blog you mean profile? In which case yes I have..
I dont ask for you to do anything in return.. as long as I helped you thats all I care about. Just go and get a good mark in it... thats what you can do
http://sazzarooo.blogspot.com/I have almost completed my assignment now but have some remaining pieces to improve on to make sure I get the grade I have worked for. Any guidance-notes or links would be GREAT!!!! I have one hour left!!!
1. Diagrams to define amplitude, wavelength, frequency and speed of waves?
2. Explanation of soundwaves speeds in different media?
3. Frequency range-audio/ultrasonic?
4. Explanation of energies related to frequency,of electromagnetic spectrum?
5. Diagram of transucer probe?
6. Why is resolution related to frequency of ultrasound?
7. 3d imaging?
8. Doppler shifted images (blood flow measurement)?
9. Schematic diagram of MRI scanner?
10. Why is a powerful magnetic field required and the interaction of H atoms with these (precession)?
11. I.R-How does wavelength depend on temparature and and how is this used to generate an image?
12. Sourse of UV-how does a lamp work?
13. Diagrm showing energy level and atoms re lasers?
14. How does laser light work on the skin in removing moles. tattoos etc?
15. Diagram of endoscope? How common are they now?
16. Schematic digram of CAT scan. Description of how detection using solid state detector works?
17. How y-rays are focussed for radiotherapy?
18. Description of the effect of radiotherapy on cancerous cells?
19. Description of Y-ray camera's and what they are specifically designed to diagnose. Include details of radiosotopes as tracers?
1. Diagrams to define amplitude, wavelength, frequency and speed of waves?
2. Explanation of soundwaves speeds in different media?
3. Frequency range-audio/ultrasonic?
4. Explanation of energies related to frequency,of electromagnetic spectrum?
5. Diagram of transucer probe?
6. Why is resolution related to frequency of ultrasound?
7. 3d imaging?
8. Doppler shifted images (blood flow measurement)?
9. Schematic diagram of MRI scanner?
10. Why is a powerful magnetic field required and the interaction of H atoms with these (precession)?
11. I.R-How does wavelength depend on temparature and and how is this used to generate an image?
12. Sourse of UV-how does a lamp work?
13. Diagrm showing energy level and atoms re lasers?
14. How does laser light work on the skin in removing moles. tattoos etc?
15. Diagram of endoscope? How common are they now?
16. Schematic digram of CAT scan. Description of how detection using solid state detector works?
17. How y-rays are focussed for radiotherapy?
18. Description of the effect of radiotherapy on cancerous cells?
19. Description of Y-ray camera's and what they are specifically designed to diagnose. Include details of radiosotopes as tracers?
All done now-I know that it isn't perfect but I am not even educated for A level physics. I have learnt a helluva lot and am really grateful to all those who responded to my questions and cries for help. Thanks. Especially F1 fanatic-you have been like gold dust. Here's the finished article for anyone who may be interested. Please keep any criticisms low profile ('cos I am done with it now in any event). Moving onto Sociology now..............>>>
Waves: There are many types of waves; sound waves, visible light waves, radio waves, microwaves, water waves etc are but a few examples. There is also a phenomenon that resembles waves such as the motion of a pendulum or a child on a swing. Waves, carry energy from one location to another and if the frequency of those waves can be changed, then we can also carry a complex signal which is capable of transmitting an idea or thought from one location to another. A wave can be described as a disturbance that travels through a medium from one location to another location. Consider a slinky wave as an example of a wave. When the slinky is stretched from end to end and is held at rest, it assumes a natural position known as the equilibrium or rest position. The coils of the slinky naturally assume this position, spaced equally far apart. To introduce a wave into the slinky, the first particle is displaced or moved from its rest position. The particle might be moved upwards or downwards, forwards or backwards; but once moved, it is returned to its original rest position. The act of moving the first coil of the slinky in a given direction and then returning it to its rest position creates a disturbance in the slinky. (cont)
Here's the finished article for anyone who may be interested. Please keep any criticisms low profile ('cos I am done with it now in any event). Moving onto Sociology now..............>>>‘The use of sound waves and electromagnetic waves in the diagnosis and treatment of medical conditions’.
Waves: There are many types of waves; sound waves, visible light waves, radio waves, microwaves, water waves etc are but a few examples. There is also a phenomenon that resembles waves such as the motion of a pendulum or a child on a swing. Waves, carry energy from one location to another and if the frequency of those waves can be changed, then we can also carry a complex signal which is capable of transmitting an idea or thought from one location to another. A wave can be described as a disturbance that travels through a medium from one location to another location. Consider a slinky wave as an example of a wave. When the slinky is stretched from end to end and is held at rest, it assumes a natural position known as the equilibrium or rest position. The coils of the slinky naturally assume this position, spaced equally far apart. To introduce a wave into the slinky, the first particle is displaced or moved from its rest position. The particle might be moved upwards or downwards, forwards or backwards; but once moved, it is returned to its original rest position. The act of moving the first coil of the slinky in a given direction and then returning it to its rest position creates a disturbance in the slinky. (cont)
We can then observe this disturbance moving through the slinky from one end to the other. A single back and forth vibration is a pulse. Whereas the repeating and periodic disturbance which moves through a medium from one location to another is referred to as a wave. A medium is a substance or material which carries the wave. It is a series of interconnected or merely interacting particles. The interactions of one particle of the medium with the next adjacent particle allows the disturbance to travel through the medium. In the case of the slinky wave, the particles are the individual coils of the slinky. In the case of a sound wave in air, the particles are the individual molecules of air. Waves involve the transport of energy without the transport of matter.
Waves come in many shapes and forms. One way to categorize waves is on the basis of the direction of movement of the individual particles of the medium relative to the direction which the waves travel.A transverse wave is a wave in which particles of the medium move in a direction perpendicular to the direction which the wave moves.
A longitudinal waveis a wave in which particles of the medium move in a direction parallel to the direction which the wave moves. A surface wave is a wave in which particles of the medium undergo a circular motion. These waves are neither longitudinal nor transverse. In longitudinal and transverse waves, all the particles in the entire bulk of the medium move in a parallel and a perpendicular direction (respectively) relative to the direction of energy transport. In a surface wave, it is only the particles at the surface of the medium which undergo the circular motion. An electromagnetic wave is a wave which is capable of transmitting its energy through a vacuum. They are produced by the vibration of electrons within atoms and they have both electric and magnetic components. The two fields are at right angles to each other. Electromagnetic radiation is an energy produced by oscillation or acceleration of an electric charge. All light waves are examples of electromagnetic waves; as are microwaves, x-rays, and TV and radio transmissions and they have both electric and magnetic components. (cont)
Waves come in many shapes and forms. One way to categorize waves is on the basis of the direction of movement of the individual particles of the medium relative to the direction which the waves travel.A transverse wave is a wave in which particles of the medium move in a direction perpendicular to the direction which the wave moves.
A longitudinal waveis a wave in which particles of the medium move in a direction parallel to the direction which the wave moves. A surface wave is a wave in which particles of the medium undergo a circular motion. These waves are neither longitudinal nor transverse. In longitudinal and transverse waves, all the particles in the entire bulk of the medium move in a parallel and a perpendicular direction (respectively) relative to the direction of energy transport. In a surface wave, it is only the particles at the surface of the medium which undergo the circular motion. An electromagnetic wave is a wave which is capable of transmitting its energy through a vacuum. They are produced by the vibration of electrons within atoms and they have both electric and magnetic components. The two fields are at right angles to each other. Electromagnetic radiation is an energy produced by oscillation or acceleration of an electric charge. All light waves are examples of electromagnetic waves; as are microwaves, x-rays, and TV and radio transmissions and they have both electric and magnetic components. (cont)
In contrast, a mechanical wave is a wave which is not capable of transmitting its energy through a vacuum. Mechanical waves require a medium in order to transport their energy from one location to another. A sound wave is an example of a mechanical wave and is therefore incapable of travelling through a vacuum. A sound wave is the result from the longitudinal motion of the particles of the medium through which the sound wave is moving. If a sound wave is moving from left to right through air, then particles of air will be displaced both rightward and leftward as the energy of the sound wave passes through it. The motion of the particles parallel (and anti-parallel) to the direction of the energy transport is what characterizes sound as a longitudinal wave. A vibrating tuning fork is capable of creating such a longitudinal wave. As the tines of the fork vibrate back and forth, they push on neighbouring air particles. The forward motion of a tine pushes air molecules horizontally to the right and the backward retraction of the tine creates a low pressure area allowing the air particles to move back to the left. Because of the longitudinal motion of the air particles, there are regions in the air where the air particles are compressed together and other regions where the air particles are spread apart. These regions are known as compressions and rarefactions respectively. The compressions are regions of high air pressure while the rarefactions are regions of low air pressure.
A sound wave, like any other wave, is introduced into a medium by a vibrating object. The vibrating object is the source of the disturbance which moves through the medium. The vibrating object which creates the disturbance could be the vocal chords of a person, the vibrating string and sound board of a guitar or violin, the vibrating tines of a tuning fork, or the vibrating diaphragm of a radio speaker. Regardless of what vibrating object is creating the sound wave, the particles of the medium through which the sound moves is vibrating in a back and forth motion at a given frequency.(cont)
A sound wave, like any other wave, is introduced into a medium by a vibrating object. The vibrating object is the source of the disturbance which moves through the medium. The vibrating object which creates the disturbance could be the vocal chords of a person, the vibrating string and sound board of a guitar or violin, the vibrating tines of a tuning fork, or the vibrating diaphragm of a radio speaker. Regardless of what vibrating object is creating the sound wave, the particles of the medium through which the sound moves is vibrating in a back and forth motion at a given frequency.(cont)
The characteristic height of a peak and depth of a trough is called the amplitude of the wave. The vertical distance between the bottom of the trough and the top of the peak is twice the amplitude.The distance between two adjacent peaks is the same no matter which two peaks you choose; so there is a fixed distance between the peaks but this distance is also the same between two adjacent troughs. This distance is called the wavelength and uses the symbol λ. The wavelength is the distance between any two adjacent points which are in phase. Two points in phase are separate by an integer (0,1,2,3,...) number of complete wave cycles. They don't have to be peaks or trough but they must be separated by a complete number of waves. To determine the frequency, we can ask how many waves go by in 1s, we work out what fraction of a waves goes by in 1 second by dividing 1 second by the time it takes T.If a wave takes 1/2 a second to go by then in 1 second two waves must go by. . The unit of frequency is the Hz or s-1.Waves move at a constant velocity. The speed is the distance you travel divided by the time you take to travel that distance. This is excellent because we know that the waves travel a distance λ in a time T. This means that we can determine the speed. The more dense the medium, the faster the waves move.(cont)
The Electromagnetic Spectrum is a continuum of all electromagnetic waves arranged according to frequency and wavelength and shows the range of wavelengths, from the longest radio wave to the shortest gamma wave. The wavelength determines what type of light the wave is. Electromagnetic radiation can be described in terms of a stream of photons, which are massless particles each travelling in a wave-like pattern and moving at the speed of light. Each photon contains a certain amount (or bundle) of energy, and all electromagnetic radiation consists of these photons. The only difference between the various types of electromagnetic radiation is the amount of energy found in the photons. Radio waves have photons with low energies, microwaves have a little more energy than radio waves, infrared has still more, then visible, ultraviolet, X-rays, and ... the most energetic of all ... gamma-rays. They can all travel through empty space and they all travel at the same speed. This speed is sometimes called The Speed of Light. It is 300 000 000 m/s (three hundred million metres per second). An electromagnetic wave travels at the speed of light and is characterized by oscillations of combined electric and magnetic fields.Gamma rays/Y-rays have so much energy that they easily pass through your body without being affected. They have the shortest wavelengths, and the highest frequencies and radioactive substances like Cobalt-60 and Caesium-137 emit gamma radiation. The gamma rays come from inside the atoms of these radioactive elements. Doctors use the gamma rays to kill cancer cells and this treatment is called radiotherapy. They also use radioactive substances as tracers. They put a tracer inside a patient's body and follow (trace) where it goes. For example, a patient with lung problems can breathe in Xenon-133 which is a gas that emits gamma rays and then a special gamma camera uses the rays to build up a picture. The patient only gets a small dose of radiation because they soon breathe out all the gas. (cont)
X-rays are used to look at the skeleton but also foreign bodies that have been ingested, teeth and certain lung conditions can be detected. X-rays are very high energy photons well beyond the range of visible light. When they hit certain materials – particularly mica – they cause the atoms of that material to jump up to a very high energy level – skipping several intermediate levels. As these electrons “fall” back into more stable orbits, they emit photons of lower energy than the X-ray. Some of these can be in the visible range and will be seen as a little flash of light – a “scintillation”. These can be seen under a microscope or detected with a digital camera. X-Rays have so much energy and such a short wavelength that they can go right through you. However, they cannot get through bone as easily as they can get through muscle. This is because your bones contain so much Calcium. X-Ray can also be used to find other problems in your body. If the doctors want to look for ulcers in your guts, they can give you a Barium meal. Like Calcium, the Barium absorbs X-Rays so the doctors can look at parts of your guts and find your ulcers
Ultraviolet radiation is produced by the Sun and ultraviolet lamps, such as sun lamps. It can damage living cells, but when carefully controlled, it can be used in hospitals to treat skin conditions and to kill harmful bacteria. UVlight is produced by exciting atoms that then emit a photon at the right energy level. However, there is no attempt to cause massive secondary emission or to make the light coherent.(i.e. laser light does this but UV doesn’t stimulate other electrons to release photons and they don’t bounce backwards and forwards as coherent light. It just produces isolated high energy UV photons). Though UV light does cause a heating effect – sunlight contains a certain amount of UV, which is what causes sunburn, skin aging, cancer and the like – it is also absorbed by certain pigments in layers just under the skin. The energy thus absorbed is used to power chemical reactions that make certain important vitamins that accelerate skin healing. These waves have very high energy and very short wave lengths; shorter than visible light. Some animals like honey bees can see ultra-violet light. Some plants have white flowers, at least you think that they are all white, but they may appear to be different colours to a honey bee because of the amounts of ultra-violet light which they reflect. (cont)
Ultraviolet radiation is produced by the Sun and ultraviolet lamps, such as sun lamps. It can damage living cells, but when carefully controlled, it can be used in hospitals to treat skin conditions and to kill harmful bacteria. UVlight is produced by exciting atoms that then emit a photon at the right energy level. However, there is no attempt to cause massive secondary emission or to make the light coherent.(i.e. laser light does this but UV doesn’t stimulate other electrons to release photons and they don’t bounce backwards and forwards as coherent light. It just produces isolated high energy UV photons). Though UV light does cause a heating effect – sunlight contains a certain amount of UV, which is what causes sunburn, skin aging, cancer and the like – it is also absorbed by certain pigments in layers just under the skin. The energy thus absorbed is used to power chemical reactions that make certain important vitamins that accelerate skin healing. These waves have very high energy and very short wave lengths; shorter than visible light. Some animals like honey bees can see ultra-violet light. Some plants have white flowers, at least you think that they are all white, but they may appear to be different colours to a honey bee because of the amounts of ultra-violet light which they reflect. (cont)
Only a small part of the electromagnetic spectrum is visible light ranging from blue/violet light to red light. Ultraviolet light has a higher frequency than blue light, whereas infrared has a lower frequency than red light; however both are invisible to the human eye. Like radio and TV waves, light waves can be used to carry information if it suitably coded. Our eyes can detect only a tiny part of the electromagnetic spectrum, called ‘visible light’. This means that there's a great deal happening around us that we're simply not aware of, unless we have instruments to detect it. Light waves are given off by anything that's hot enough to glow. This is how light bulbs work - an electric current heats the lamp filament to around 3,000 degrees, and it glows white-hot. White light is actually made up of a whole range of colours, mixed together. We can see this if we pass white light through a glass prism - the violet light is bent ("refracted") more than the red, because it has a shorter wavelength - and we see a rainbow of colours. Light waves can also be made using a laser. This works differently to a light bulb, and produces "coherent" light. Lasers can be used to treat a wide number of disorders i.e. unwanted hair, eye treatment, skin problems, cosmetic surgery and so on.An endoscope is a device with a light attached, used to look inside a body cavity or organ. It uses two fiber optic lines. A "light fiber" carries light into the body cavity and an "image fiber" carries the image of the body cavity back to the physician's viewing lens. There is also a separate port to allow for administration of drugs, suction, and irrigation. This port may also be used to introduce small folding instruments such as forceps, scissors, brushes, snares and baskets for tissue excision (removal), sampling, or other diagnostic and therapeutic work. Endoscopes may be used in conjunction with a camera or video recorder to document images of the inside of the joint or chronicle an endoscopic procedure.An optical fibre is like a “tunnel” with extremely reflective walls. By packing a bundle of these fibres together (several hundreds, if not thousands), each can transmit part of an image back to either a microscope or a digital camera to be magnified. Note that some of the fibres can be used to carry illumination down to the far end, too. The fibres used in an endoscope are generally made either from glass or from a special kind of plastic that can be extruded very, very thin – only a few millionths of a meter in diameter. At that thickness, glass becomes surprisingly flexible. (cont)
Infrared rays are commonly given off by very hot objects and when these infrared rays are absorbed by something, its temperature rises. Our bodies radiate a range of infrared frequencies and the frequency of the radiation depends on the temperature of the part of the body concerned. Infra-red waves have a very short length and are just below visible red light in the electromagnetic spectrum ("Infra" means "below"). They are used for many tasks, for example, TV remote controls and video recorders, and physiotherapists use heat lamps to help heal sports injuries. Also, infra red pictures may reveal tumours. Finally, every object gives off IR waves, so we can use them to "see in the dark"; night sites for weapons sometimes use a sensitive IR detector. Wireless and wired cameras can all be focused from near (less than 1 cm) to infinity by adjusting the lens and have inbuilt smart features such as back light compensation (BLC-able to adjust to different light condition), night vision cameras can see in total darkness, the IR diodes on the front of the camera send out an infrared beam allowing amazing quality without the need for a light source.Microwaves have wavelengths that are shorter than radio waves but longer than infrared. Microwave ovens produce microwaves at just the right frequency (2.45 GHz, or 2.45 thousand million hertz) for water and fat molecules to absorb the energy carried by the microwaves and as the molecules move about faster, the water or fat gets hotter. Microwaves can be created by making electrons move around in a small metal box with no air in it and this is called a magnetron; all microwave ovens have a magnetron to produce the microwaves for cooking. Radar uses microwaves with higher frequencies than microwave ovens (about 10 GHz). Metal objects reflect the waves very strongly and so the radar machine can work out the position and speed of cars, ships and aeroplanes from the reflections.Radio waves are made when electrons move up and down inside an aerial and these waves have the longest lengths and the lowest frequencies. High frequency radio waves can carry a lot of information and very High Frequency (VHF) waves are used to carry FM radio broadcasts., whereas Ultra High Frequency waves are used to carry TV broadcasts. These high frequency radio waves pass straight through the ionosphere. You can still pick up television signals from other parts of the world if they are bounced off a communications satellite. Radio waves have a much longer wavelength that light waves. The longest waves are several kilometres in length. The shortest ones are only millimetres long. Radio waves will make the electrons in a piece of copper wire move; this means that they generate electric currents in the wire. In fact it works both ways: alternating currents in a copper wire generate electromagnetic waves and electromagnetic waves generate alternating currents. The electric currents at "radio frequencies" (rf) are used by radio and television transmitters and receivers. (Cont)
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