The following passage of four paragraphs contains a number of errors (somewhere between 5 and 10). Rewrite this passage, correcting any errors that are contained there. It should be possible to do this by replacing just one word within a sentence with another. A pulse of radio waves is used to excite some of the protons from their lower to higher energy spin states until there is the same number in each. At the end of the pulse when the radio frequency radiation is removed, the proton spins gradually return to their original population distribution within the two states. This is called resonance. Radio waves are re-emitted and these are detected by the same coils that were used to generate the original pulse. The frequency of the radio waves received from different parts of the body is mapped out into an array of tiny blocks known as voxels. Each voxel is assigned a level of grey-scale brightness on an image corresponding to the signal strength, allowing detailed cross-sections of the patient's body to be built up. The frequency at which the radiation is re-emitted depends on the local environment of the protons from which the radiation is emitted, and hence on the kid of tissue they are in. If sufficient time is given from the end of the radio pulse to measure the full extent of the emitted radio wave signal, then the image produced maps out the density of tissue through the body. This is called a proton density weighted image. Alternatively, the radio wave signal can be measured for a relatively short period of time after the end of the pulse and gives rise to a so-called t1 weight image. If the measurement of the signal is over a relatively longer time but delayed somewhat after the end of the radio wave pulse, then the image is said to be T2 weighted. By selecting how the image is weight, the physician can decide the best way to show resolution between tissues of interest. Determining the signal strength from each voxel is a complicated process that requires the use of three more electromagnets coiled around the main magnet. These are known as radiofrequency coils and are arranged perpendicularly to each other. One of these sets of coils has its axis aligned in the same direction as the main magnet and can be used to alter the overall magnetic field so that the magnetic reverberation is confined to a thin slice perpendicular to that axis. The other two sets of coils are then switched in succession and signals recorded in a way which allows the signal strength for each of the voxels within the slice to be determined. The speed of the measurements is limited by the length of the pulse sequence repetition times which may be several minutes in length. The whole process of producing an MRI scan is therefore considerably longer than that required for an equivalent CT scan.
Quantum mechanics and hydrogen atom
Consider an electron of mass m moves with the velocity v in a hydrogen atom. If an electron is at a distance r from the proton, then the potential energy function of the electron can be written as follows:
Isotopes of Hydrogen Atoms
To understand isotopes, it's easiest to learn the simplest system. Hydrogen, the most basic nucleus, has received a great deal of attention. Several of the results seen in more complex nuclei can be seen in hydrogen isotopes. An isotope is a nucleus of the same atomic number (Z) but a different atomic mass number (A). The number of neutrons present in the nucleus varies with respect to the isotope.
Mass of Hydrogen Atom
Hydrogen is one of the most fundamental elements on Earth which is colorless, odorless, and a flammable chemical substance. The representation of hydrogen in the periodic table is H. It is mostly found as a diatomic molecule as water H2O on earth. It is also known to be the lightest element and takes its place on Earth up to 0.14 %. There are three isotopes of hydrogen- protium, deuterium, and tritium. There is a huge abundance of Hydrogen molecules on the earth's surface. The hydrogen isotope tritium has its half-life equal to 12.32 years, through beta decay. In physics, the study of Hydrogen is fundamental.
The following passage of four paragraphs contains a number of errors (somewhere between 5 and 10). Rewrite this passage, correcting any errors that are contained there. It should be possible to do this by replacing just one word within a sentence with another.
A pulse of radio waves is used to excite some of the protons from their lower to higher energy spin states until there is the same number in each. At the end of the pulse when the radio frequency
The frequency at which the radiation is re-emitted depends on the local environment of the protons from which the radiation is emitted, and hence on the kid of tissue they are in. If sufficient time is given from the end of the radio pulse to measure the full extent of the emitted radio wave signal, then the image produced maps out the density of tissue through the body. This is called a proton density weighted image. Alternatively, the radio wave signal can be measured for a relatively short period of time after the end of the pulse and gives rise to a so-called t1 weight image. If the measurement of the signal is over a relatively longer time but delayed somewhat after the end of the radio wave pulse, then the image is said to be T2 weighted. By selecting how the image is weight, the physician can decide the best way to show resolution between tissues of interest.
Determining the signal strength from each voxel is a complicated process that requires the use of three more
The speed of the measurements is limited by the length of the pulse sequence repetition times which may be several minutes in length. The whole process of producing an MRI scan is therefore considerably longer than that required for an equivalent CT scan.
Step by step
Solved in 2 steps
