Definition: “Materials which does not have permanent magnetic dipoles” are termed as Diamagnetic materials. or The substances which when placed in a magnetic field become weakly magnetised in a direction opposite to that of the applied magnetising field are called diamagnetic substances. Examples: Gold, Quartz, Water, Copper, Zinc, Germanium, Silver, Lead, Silica, Helium, Bismuth etc.,
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Now, we are going to study the various types of magnetic materials in terms of the magnetic properties of the atomic dipoles and the interactions between them. Very first distinctions is based on whether the atoms carry permanent magnetic dipoles or not. Materials not having permanent magnetic moment Diamagnetic materials Materials which lack permanent dipoles
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The macroscopic magnetic properties of a substance are a consequence of magnetic moments associated with individual electrons. The electrons in an atom revolved around the nucleus in different orbits. Each electron in an atom has magnetic moments that originate from the following sources. The orbital magnetic moment of electrons (the motion of electrons in the
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Photolytic degradation is the degradation of photodegradable molecules caused by the absorption of photons, particularly those wavelengths found in sunlight, such as infrared radiation, visible light, and ultraviolet light. Some molecules get activated by the heat of light which increases the reaction rate. Drugs which get chemically degraded in the presence of light are photosensitive
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In pharmacy, micromeritics is employed for: Release and Dissolution: Clinically, the particle size and surface area of a drug can affect its release from dosage forms administered orally, parenterally, rectally, and topically. Finely powdered drug has a high surface area, hence gets easily dissolved in dissolution fluids in vivo, thereby enhancing the drug solubility and
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Figure shows a schematic diagram of Coulter counter equipment used for determining the particle volume. The equipment is applicable to materials of particle size ranging between 0.5-1000μm. Principle The principle involved in the working of this instrument is that when the particles suspended in a conducting liquid passes through a small orifice (having electrodes on
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Definition : When conductor (metal or semiconductor) carrying a current is placed in a transverse magnetic field, an electric field is produced inside the conductor in a direction normal to both the current and the magnetic field. This phenomenon is known as “Hall effect” and the generated voltage is called “Hall voltage”. This effect is
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S.NO Intrinsic semiconductors Extrinsic semiconductors 1. Semiconductor in a pure form is called intrinsic semiconductor. Semiconductor which are doped with impurity is called extrinsic semiconductor. 2. Here the charge carriers are produced only due to thermal agitation Here the charge carriers are produced due to impurities and may also be produced due to thermal agitation.
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The variation of carrier concentration with temperature for a n-type semi conductor is shown in Fig. At 0K both the conduction band and valence band are free from any charge carriers and hence conductivity is zero. Now, when the temperature is slowly increased, the donor atoms get ionized and hence, the electron concentration in conduction band increased.
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Emulsions are estimated for their flow behaviour. The flow related attributes desirable for the performance of an emulsion are: Removal of an emulsion from a bottle or tube. Flow of an emulsion through a hypodermic needle. Spreadability of an emulsion on the skin. Stress induced flow changes during manufacture (milling). Dilute emulsions possess Newtonian flow,
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