Results 1–10 of 10 for Gauss%E2%80%99 law for electrostatics
Gauss’ law describes the relation between charge and electric field in static situations, so it is equivalent to Coulomb’s law, which can be derived from Gauss’ law. Gauss’ law states that the net flux of electric field, Φ, through an imaginary closed surface, S, - a Gaussian surface - is equal to the net charge, q, inside that closed surface:
where electric flux Φ through Gaussian surface is given by:
ε0 is the permittivity constant and dS is a surface element.
The magnetic field B due to a current-carrying conductor can be determined by Biot-Savart law. The contribution to magnetic field set up at distance r by the current element IdL is given by expression:
where μ0 is permeability constant. It plays a role in magnetic problems equivalent to the role of permittivity constant μ0 in electrostatics problems. In order to obtain B, contributions of all current elements have to be integrated. In case of a long straight conductor, carrying current I, Biot-Savart law gives:
SI unit for magnetic field B is tesla (T).
Permaeability constant μ0 has value 4π×10-7 T m A-1.
Dielectric constant or permittivity (ε) is an index of the ability of a substance to attenuate the transmission of an electrostatic force from one charged body to another. The lower the value, the greater the attenuation. The standard measurement apparatus utilises a vacuum whose dielectric constant is 1. In reference to this, various materials interposed between the charged terminal have the following value at 20 °C:
vacuum | 1 |
air | 1.00058 |
glass | 3 |
benzene | 2.3 |
acetic acid | 6.2 |
ammonia | 15.5 |
ethanol | 25 |
glycerol | 56 |
water | 81 |
The exceptionally high value for water accounts for its unique behaviour as a solvent and in electrolytic solutions. Dielectric constant values decrease as the temperature rises.
Faraday constant (F) is the electric charge of 1 mol of singly charged positive ions.
where NA is Avogadro’s constant (6.022×1023 mol-1) and e is the elementary charge (1.602×10-19 C).
Gaussian system of units is a hybrid system used in electromagnetic theory, which combines features of both the electrostatic cgs subsystem (esu) and electromagnetic cgs subsystem (emu). With three base units, it uses em units in magnetism and es units in electrostatics. This involves using the constant c (the velocity of light in vacuum) to interrelate these sets of units.
Metallic bond is a electrostatic attraction binding the positive ions of a solid metal together by means of a "sea" of delocalised valence electrons
If a small amount of charge experience a force, there is an electric field in the vicinity. Electric field E is defined in terms of electrostatic force F that would be exerted on positive test charge qp placed in the field:
SI unit for electric field is N C-1, or V m-1.
The electric field due to a point charge q at distance r from it given by:
where ε0 is permittivity constant, and is εo=8.85×10-12 C2 N-1 m-2.
Silver coulometer consists of a platinum vessel which acts as a cathode and contains a solution of pure silver nitrate as an electrolyte (c(AgNO3) = 1 mol/L). A rod of pure silver enclosed in a porous pot acts as the anode. The current density at the anode should not exceed 0.2 Acm-2. After electrolysis, the electrolyte is taken out and the platinum vessel is washed, dried and weighed. The increase in the weight gives the amount of silver deposited (96500 C of electricity deposits 107.88 g of silver). From the mass of the silver deposited, the coulomb involved in the reaction can be calculated.
Generalic, Eni. "Gauss%E2%80%99 law for electrostatics." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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