write short noteson: (1) Isobars; (2) double beta decay; (3) nuclear magnetic resonance.
Answers
Answer:
Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are perturbed by a weak oscillating magnetic field (in the near field[1]) and respond by producing an electromagnetic signal with a frequency characteristic of the magnetic field at the nucleus. This process occurs near resonance, when the oscillation frequency matches the intrinsic frequency of the nuclei, which depends on the strength of the static magnetic field, the chemical environment, and the magnetic properties of the isotope involved; in practical applications with static magnetic fields up to ca. 20 tesla, the frequency is similar to VHF and UHF television broadcasts (60–1000 MHz). NMR results from specific magnetic properties of certain atomic nuclei. Nuclear magnetic resonance spectroscopy is widely used to determine the structure of organic molecules in solution and study molecular physics and crystals as well as non-crystalline materials. NMR is also routinely used in advanced medical imaging techniques, such as in magnetic resonance imaging (MRI).
Answer:
1. Isobars -: Isobars are atoms or nuclides of separate chemical elements having the same number of nucleons (protons+ neutrons). The name was given by Alfred Walter Stewart in 1918. It is originally taken from the combination of Greek words- isos means equal and bar means weight.
2. double beta decay -: Beta decay occurs in one of the two ways: a) when the nucleus emits an electron and an antineutrino in a process that changes a neutron to a proton b) when the nucleus emits a positron and a neutrino in a process that changes a proton to a neutron.
3. nuclear magnetic resonance -: Nuclear magnetic resonance (NMR) spectroscopy is the study of molecules by recording the interaction of radiofrequency (Rf) electromagnetic radiations with the nuclei of molecules placed in a strong magnetic field.