a.As the star gets bigger, the force of gravity also gets bigger, while the radiation pressure stays the same.
b.The star fuses more hydrogen as it gets near the end of its life, then the fusion of hydrogen is converted to gravity.
c.Near the end of its life, a star runs out of hydrogen to fuse, and fusion is what creates the radiation pressure.
d.Gravity increases with time, so the older a star gets, the more it is affected by the force of gravity.How does the inward force of gravity overcome the outward force of radiation pressure during the end of a star?
As discussed in my answer at:
http://answers.yahoo.com/question/index;鈥?/a>
the answer is c).
Wednesday, February 29, 2012
What's the difference between radiation therapist and radiologic technologist?
My major is radiation therapist(I know about this), but my major is impacted. I was looking at other colleges and one have radiologic technologist. I was wondering what is the difference between those two. And if it's similar why does a radiologic technologist gets paid less than the radiation therapist.
** I live in CA, i dont know if that helpsWhat's the difference between radiation therapist and radiologic technologist?
Radiologic technologists do x-ray, CT, MRI, etc. Radiation therapists treat cancer patients. Why do we make so much less? I'd like to know the answer to that one too.
** I live in CA, i dont know if that helpsWhat's the difference between radiation therapist and radiologic technologist?
Radiologic technologists do x-ray, CT, MRI, etc. Radiation therapists treat cancer patients. Why do we make so much less? I'd like to know the answer to that one too.
What wavelength of radiation must be used to eject electrons with a velocity of 1.3 103 km路s-1?
The work function for chromium metal is 4.37 eV. What wavelength of radiation must be used to eject electrons with a velocity of 1.3 103 km路s-1?What wavelength of radiation must be used to eject electrons with a velocity of 1.3 103 km路s-1?
this is photoelectric effect
h蠀=w+k
k kinetic energy
w work function
h蠀 photon energy
h planck's constant
蠀 frequency
v speed of eject electron 1.3103 x 10鲁 m/s
m electron mass
k=陆m.v虏
h蠀=w+陆m.v虏
h蠀=E photon energy
E/h=蠀
c speed of the light
c/蠀=位 -%26gt;wave length of radiation
this is photoelectric effect
h蠀=w+k
k kinetic energy
w work function
h蠀 photon energy
h planck's constant
蠀 frequency
v speed of eject electron 1.3103 x 10鲁 m/s
m electron mass
k=陆m.v虏
h蠀=w+陆m.v虏
h蠀=E photon energy
E/h=蠀
c speed of the light
c/蠀=位 -%26gt;wave length of radiation
What is cosmic radiation and the scattering experiment?
GCSE. Please make the answer idiot proof! I think it's something like background radiation, is that right?What is cosmic radiation and the scattering experiment?
'In cosmology, the cosmic microwave background radiation CMB (also CMBR, CBR, MBR, and relic radiation) is a form of electromagnetic radiation filling the universe. With a traditional optical telescope, the space between stars and galaxies (the background) is pitch black. But with a radio telescope, there is a faint background glow, almost exactly the same in all directions, that is not associated with any star, galaxy, or other object. This glow is strongest in the microwave region of the radio spectrum, hence the name cosmic microwave background radiation. The CMB's discovery in 1964 by astronomers Arno Penzias and Robert Wilson was the culmination of work initiated in the 1940s, and earned them the 1978 Nobel Prize.
The CMBR is well explained by the Big Bang theory 鈥?when the universe was young, before the formation of stars and planets, it was smaller, much hotter, and filled with a uniform glow from its red-hot fog of hydrogen plasma. As the universe expanded, both the plasma and the radiation filling it grew cooler. When the universe cooled enough, stable atoms could form. These atoms could no longer absorb the thermal radiation, and the universe became transparent instead of being an opaque fog. The photons that were around at that time have been propagating ever since, though growing fainter and less energetic, since the exact same photons fill a larger and larger universe. This is the source for the term relic radiation, another name for the CMBR.
Precise measurements of cosmic background radiation are critical to cosmology, since any proposed model of the universe must explain this radiation. The CMBR has a thermal black body spectrum at a temperature of 2.725 K, thus the spectrum peaks in the microwave range frequency of 160.2 GHz, corresponding to a 1.9 mm wavelength. The glow is almost but not quite uniform in all directions, and shows a very specific pattern equal to that expected if the inherent randomness of a red-hot gas is blown up to the size of the universe. In particular, the spatial power spectrum (how much difference is observed versus how far apart the regions are on the sky) contains small anisotropies, or irregularities, which vary with the size of the region examined. They have been measured in detail, and match to within experimental error what would be expected if small thermal fluctuations had expanded to the size of the observable space we can detect today.
Although many different processes might produce the general form of a black body spectrum, no model other than the Big Bang has yet explained the fluctuations. As a result, most cosmologists consider the Big Bang theory of the universe to be the best explanation for the CMBR. ...'
'.... Measurements of the CMB have made the inflationary Big Bang theory the standard model of the earliest eras of the universe.This theory predicts that the initial conditions for the universe are originally random in nature, and follow a roughly Gaussian distribution. The power spectrum of these fluctuations has been calculated, and agrees startlingly well with the observations, although certain observables, for example the overall amplitude of the fluctuations, are more or less free parameters of the cosmic inflation model. ...'
'... The CMB gives a snapshot of the Universe when, according to standard cosmology, the temperature dropped enough to allow electrons and protons to form hydrogen atoms, thus making the universe transparent to radiation. When it originated some 400,000 years after the Big Bang 鈥?this time period is generally known as the "time of last scattering" or the period of recombination or decoupling 鈥?the temperature of the Universe was about 3,000 K. This corresponds to an energy of about 0.25 eV, which is much less than the 13.6 eV ionization energy of hydrogen. Since then, the temperature of the radiation has dropped by a factor of roughly 1100 due to the expansion of the Universe. As the universe expands, the CMB photons are redshifted, making the radiation's temperature inversely proportional to the Universe's scale length. ...'
'... The anisotropy of the cosmic microwave background is divided into two sorts: primary anisotropy 鈥?which is due to effects which occur at the last scattering surface and before 鈥?and secondary anisotropy 鈥?which is due to effects, such as interactions with hot gas or gravitational potentials, between the last scattering surface and the observer. ...'
'... Subsequent to the discovery of the CMB, hundreds of cosmic microwave background experiments have been conducted to measure and characterize the signatures of the radiation. The most famous experiment is probably the NASA Cosmic Background Explorer (COBE) satellite that orbited in 1989鈥?996 and which detected and quantified the large scale anisotropies at the limit of its detection capabilities. Inspired by the initial COBE results of an extremely isotropic and homogeneous background, a series of ground- and balloon-based experiments quantified CMB anisotropies on smaller angular scales over the next decade. ... In June 2001, NASA launched a second CMB space mission, WMAP, to make much more precise measurements of the large scale anisotropies over the full sky. The first results from this mission, disclosed in 2003, were detailed measurements of the angular power spectrum to below degree scales, tightly constraining various cosmological parameters. The results are broadly consistent with those expected from cosmic inflation as well as various other competing theories, and are available in detail at NASA's data center for Cosmic Microwave Background (CMB) (see links below). Although WMAP provided very accurate measurements of the large angular-scale fluctuations in the CMB (structures about as large in the sky as the moon), it did not have the angular resolution to measure the smaller scale fluctuations which had been observed using previous ground-based interferometers. ...(Wikipedia)'.
'In cosmology, the cosmic microwave background radiation CMB (also CMBR, CBR, MBR, and relic radiation) is a form of electromagnetic radiation filling the universe. With a traditional optical telescope, the space between stars and galaxies (the background) is pitch black. But with a radio telescope, there is a faint background glow, almost exactly the same in all directions, that is not associated with any star, galaxy, or other object. This glow is strongest in the microwave region of the radio spectrum, hence the name cosmic microwave background radiation. The CMB's discovery in 1964 by astronomers Arno Penzias and Robert Wilson was the culmination of work initiated in the 1940s, and earned them the 1978 Nobel Prize.
The CMBR is well explained by the Big Bang theory 鈥?when the universe was young, before the formation of stars and planets, it was smaller, much hotter, and filled with a uniform glow from its red-hot fog of hydrogen plasma. As the universe expanded, both the plasma and the radiation filling it grew cooler. When the universe cooled enough, stable atoms could form. These atoms could no longer absorb the thermal radiation, and the universe became transparent instead of being an opaque fog. The photons that were around at that time have been propagating ever since, though growing fainter and less energetic, since the exact same photons fill a larger and larger universe. This is the source for the term relic radiation, another name for the CMBR.
Precise measurements of cosmic background radiation are critical to cosmology, since any proposed model of the universe must explain this radiation. The CMBR has a thermal black body spectrum at a temperature of 2.725 K, thus the spectrum peaks in the microwave range frequency of 160.2 GHz, corresponding to a 1.9 mm wavelength. The glow is almost but not quite uniform in all directions, and shows a very specific pattern equal to that expected if the inherent randomness of a red-hot gas is blown up to the size of the universe. In particular, the spatial power spectrum (how much difference is observed versus how far apart the regions are on the sky) contains small anisotropies, or irregularities, which vary with the size of the region examined. They have been measured in detail, and match to within experimental error what would be expected if small thermal fluctuations had expanded to the size of the observable space we can detect today.
Although many different processes might produce the general form of a black body spectrum, no model other than the Big Bang has yet explained the fluctuations. As a result, most cosmologists consider the Big Bang theory of the universe to be the best explanation for the CMBR. ...'
'.... Measurements of the CMB have made the inflationary Big Bang theory the standard model of the earliest eras of the universe.This theory predicts that the initial conditions for the universe are originally random in nature, and follow a roughly Gaussian distribution. The power spectrum of these fluctuations has been calculated, and agrees startlingly well with the observations, although certain observables, for example the overall amplitude of the fluctuations, are more or less free parameters of the cosmic inflation model. ...'
'... The CMB gives a snapshot of the Universe when, according to standard cosmology, the temperature dropped enough to allow electrons and protons to form hydrogen atoms, thus making the universe transparent to radiation. When it originated some 400,000 years after the Big Bang 鈥?this time period is generally known as the "time of last scattering" or the period of recombination or decoupling 鈥?the temperature of the Universe was about 3,000 K. This corresponds to an energy of about 0.25 eV, which is much less than the 13.6 eV ionization energy of hydrogen. Since then, the temperature of the radiation has dropped by a factor of roughly 1100 due to the expansion of the Universe. As the universe expands, the CMB photons are redshifted, making the radiation's temperature inversely proportional to the Universe's scale length. ...'
'... The anisotropy of the cosmic microwave background is divided into two sorts: primary anisotropy 鈥?which is due to effects which occur at the last scattering surface and before 鈥?and secondary anisotropy 鈥?which is due to effects, such as interactions with hot gas or gravitational potentials, between the last scattering surface and the observer. ...'
'... Subsequent to the discovery of the CMB, hundreds of cosmic microwave background experiments have been conducted to measure and characterize the signatures of the radiation. The most famous experiment is probably the NASA Cosmic Background Explorer (COBE) satellite that orbited in 1989鈥?996 and which detected and quantified the large scale anisotropies at the limit of its detection capabilities. Inspired by the initial COBE results of an extremely isotropic and homogeneous background, a series of ground- and balloon-based experiments quantified CMB anisotropies on smaller angular scales over the next decade. ... In June 2001, NASA launched a second CMB space mission, WMAP, to make much more precise measurements of the large scale anisotropies over the full sky. The first results from this mission, disclosed in 2003, were detailed measurements of the angular power spectrum to below degree scales, tightly constraining various cosmological parameters. The results are broadly consistent with those expected from cosmic inflation as well as various other competing theories, and are available in detail at NASA's data center for Cosmic Microwave Background (CMB) (see links below). Although WMAP provided very accurate measurements of the large angular-scale fluctuations in the CMB (structures about as large in the sky as the moon), it did not have the angular resolution to measure the smaller scale fluctuations which had been observed using previous ground-based interferometers. ...(Wikipedia)'.
What is the shortest wavelength present in the radiation from an x-ray machine?
What is the shortest wavelength present in the radiation from an x-ray machine whose operating potential difference is 50,000 V?
I've had the numbers and equations explained but it is totally over my head.What is the shortest wavelength present in the radiation from an x-ray machine?
The speed of the electron striking the anode is a function of tube voltage. As the voltage (V) varies, so will the energy of the electron as it strikes the anode. This contributes to the ‘white’ or continuous spectrum of X-ray wavelengths emitted from an X-ray tube. The shortest wavelength emitted is a function of the maximum voltage applied to the tube, and is given by the Duane-Hunt Law which states that “the wavelength of greatest intensity is approximately twice that of the shortest wavelength (SWL) emitted”. The minimum wavelength generated is given by the equation below:
SWL = 1243/Vtube (SWL in nanometers)
Gives at 50'000V a Shortest Wavelength of 0.02486nmflight simulator games fashion week 2011
I've had the numbers and equations explained but it is totally over my head.What is the shortest wavelength present in the radiation from an x-ray machine?
The speed of the electron striking the anode is a function of tube voltage. As the voltage (V) varies, so will the energy of the electron as it strikes the anode. This contributes to the ‘white’ or continuous spectrum of X-ray wavelengths emitted from an X-ray tube. The shortest wavelength emitted is a function of the maximum voltage applied to the tube, and is given by the Duane-Hunt Law which states that “the wavelength of greatest intensity is approximately twice that of the shortest wavelength (SWL) emitted”. The minimum wavelength generated is given by the equation below:
SWL = 1243/Vtube (SWL in nanometers)
Gives at 50'000V a Shortest Wavelength of 0.02486nm
How much radiation is really being emitted into the atmosphere?
Phones, TV's, microwaves... what next? It's all being emitted into the atmosphere but how much radiation can we really take when there're new emerging technologies being invented all the time. When's enough really going to be enough?How much radiation is really being emitted into the atmosphere?
You are correct, that there are more and more things using the newer technologies.
We also need to think about the fact that there are many types of radiation. visible light and heat are radiation.
Good working microwaves should not leak any radiation. RADAR is the same radiation and is used .microwaves are also used to send tv and radio communication between towers.
The infrared used in a tv remote does not effect us.
There is greater radiation as w fly cross country. Pilots are only allowed so many cross country flights per month because of this radiation from outer space.
We do need to reduce the number of xrays we get.
Avoid ultraviolet (black light)
Keep LASER pointer beams from yes.Use ear piece instead of holding cell phone to the ear.
Use sun block, often
Sit away from tv's
Use an ear piece instead of holding the cell phone to the ear
There is natural radiation from radioactive materials being released all the time. [example is uranium which is in most rocks turning into radon. We do not want radon in our basement]
But, radiation being released into the air does not continue on and on and effect us that much.How much radiation is really being emitted into the atmosphere?
The key thing to consider is not the amount of radiation you receive but the amount of radiation that actually interacts with your body...
Every second about 6,000 trillion neutrinos pass through your body and, yet, there is really no health problem associated with that radiation source. The reason is that neutrinos interact very weakly with any kind of matter...
You are correct, that there are more and more things using the newer technologies.
We also need to think about the fact that there are many types of radiation. visible light and heat are radiation.
Good working microwaves should not leak any radiation. RADAR is the same radiation and is used .microwaves are also used to send tv and radio communication between towers.
The infrared used in a tv remote does not effect us.
There is greater radiation as w fly cross country. Pilots are only allowed so many cross country flights per month because of this radiation from outer space.
We do need to reduce the number of xrays we get.
Avoid ultraviolet (black light)
Keep LASER pointer beams from yes.Use ear piece instead of holding cell phone to the ear.
Use sun block, often
Sit away from tv's
Use an ear piece instead of holding the cell phone to the ear
There is natural radiation from radioactive materials being released all the time. [example is uranium which is in most rocks turning into radon. We do not want radon in our basement]
But, radiation being released into the air does not continue on and on and effect us that much.How much radiation is really being emitted into the atmosphere?
The key thing to consider is not the amount of radiation you receive but the amount of radiation that actually interacts with your body...
Every second about 6,000 trillion neutrinos pass through your body and, yet, there is really no health problem associated with that radiation source. The reason is that neutrinos interact very weakly with any kind of matter...
What is the difference between Chemo therahy and Radiation?
What is the difference between Chemo therahy and Radiation?
Which one is stronger than the other, please help me to explain.What is the difference between Chemo therahy and Radiation?
I am a radiotherapist.
Chemo was explained quite well by Angel_Blue. It is a drug, it can be delivered in the form of an injection, via a drip, as a tablet or even in a cream. the side effects are often systemic - ie. they affect the whole body.
Radiotherapy is the use of very high energy x-rays. It is usually used to treat cancer, but can be used for some other illnesses. it can be used to cure cancer, or just to reduce pain or othe problems associated with cancer. the side effects are usually localised ie- they only affect the area actually treated. a course of Radiotherapy can be given in 1 treatment, or as many as 37 treatments, they are usually given once a day, 5 days a week.What is the difference between Chemo therahy and Radiation?
Chemotherapy involves putting toxic drugs into a person's body through an I.V needle in your arm. Radiation is what's used in x-rays. I take chemo, so i don't know exactly how radiation works. I DO know chemo drugs have all sorts of side effects, and none of them are nice. Vomiting, nausea, weight loss, tired ALL the time, sleeping too much, hair loss.... and more. I know radiation gives you blisters like a sunburn, that pop and flake like a REAL sunburn, but that's all i know. Try looking it up online somewhere.What is the difference between Chemo therahy and Radiation?
Chemo is a drug and radiation is x ray radiation.
Which one is stronger than the other, please help me to explain.What is the difference between Chemo therahy and Radiation?
I am a radiotherapist.
Chemo was explained quite well by Angel_Blue. It is a drug, it can be delivered in the form of an injection, via a drip, as a tablet or even in a cream. the side effects are often systemic - ie. they affect the whole body.
Radiotherapy is the use of very high energy x-rays. It is usually used to treat cancer, but can be used for some other illnesses. it can be used to cure cancer, or just to reduce pain or othe problems associated with cancer. the side effects are usually localised ie- they only affect the area actually treated. a course of Radiotherapy can be given in 1 treatment, or as many as 37 treatments, they are usually given once a day, 5 days a week.What is the difference between Chemo therahy and Radiation?
Chemotherapy involves putting toxic drugs into a person's body through an I.V needle in your arm. Radiation is what's used in x-rays. I take chemo, so i don't know exactly how radiation works. I DO know chemo drugs have all sorts of side effects, and none of them are nice. Vomiting, nausea, weight loss, tired ALL the time, sleeping too much, hair loss.... and more. I know radiation gives you blisters like a sunburn, that pop and flake like a REAL sunburn, but that's all i know. Try looking it up online somewhere.What is the difference between Chemo therahy and Radiation?
Chemo is a drug and radiation is x ray radiation.
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