Cgs system of units

The authors of this research selected units which could be written with maximum simplification to report their results. We must replace the factors which have canceled out. Assuming that the cgs system of units was used throughout, we note that possible units for H are grams per square centimeter and possible unts for C2 are grams per cubic centimeter, which yield the required units for n/c2 Note that these units of H must be multiplied by the gravitational constant to give H in dynes per square centimeter ... 

Coulomb s law. This relationship poses no particular difficulties as a qualitative statement the problem arises when we attempt to calculate something with it, since the proportionality constant depends on the choice of units. In the cgs system of units, the electrostatic unit of charge is defined to produce a force of 1 dyne when two such charges are separated by a distance of 1 cm. In the cgs system the proportionality factor in Coulomb s law is unity and is dimensionless. For charges under vacuum we write... 

Before closing this section, it is worth mentioning that the hyperpolarizability tensors are complex quantities usually given in the old cgs system of units of esu (electrostatic units). The transformation into the International System is readily obtained with the relationship ... 

The abbreviation au stands for atomic units , which is a system of units meant to simplify the equations of molecular and atomic quantum mechanics. The units of the au system are combinations of the fundamental units of mass (mass of the electron), charge (charge of the electron), and Planck s constant. By setting these three quantities equal to unity one gets simpler equations. The au system has a simple relation to the SI and Gaussian (cgs) systems of units. For example, 1 au of length = aQ (Bohr radius) = 5.29 x 10"9 cm =... 

A short digression on units is perhaps appropriate here. We shall use either Gaussian rrrrits in this book or, much more frequently, Hartree s atomic units. Gaussian units, as far as we are concerned, are identical with the old cgs system of units with the added proviso that charges are measured in unnamed electrostatic units, esu. The value of e is thus 4.803206808 X 10 esu. Keeping this number at hand is all that will be required to use Gaussian rmits in this book. 

Note that above we so far employed the absolute (CGS) system of units. Since in most publications deovted to electrolytes SI (MKS) system is usually used, we shall below duplicate the formula for both systems (if these formulas... 

The unconventional dimension of kg/m3 is the result of our consistent application of the SI rather than the older CGS system of units. The fundamental SI units are meter, kilogram (mass), second, ampere, Kelvin (K) an Candela, while force, weight, pressure etc. are derived magnitudes. For conversion tables see the back flyleaf of this volume. 

Source represents the emission of radiant energy, which may be per unit time or area or both. In the cgs system of units, radiant energy is measured in ergs and in the inks system it is measured in joules. Other radiometric units evolve as listed in Table 16.1. 

This is Coulomb s law. The units for charge, field strength, and force are made compatible by specifying the units of the factor of proportionality -y. For example, if y = 4-ir/e, where e is the dielectric constant of the medium, the units are in terms of cgs or absolute electrostatic system (esu). Since the dielectric constant for air is essentially 1, for aerosols using the cgs system of units, -y = 4u. 

In the cgs system of units, if the pressure change is in grams per square centimeter), the distance is in cm, and the viscosity value is in poisies (grams/cm-sec), with the velocity in cm/sec, then the dimensions of K will be cm /sec. ... 

A given symbol may represent more than one property. The appropriate meaning should be apparent from the context. The equations given in Sec. 15 reflect the use of the SI or cgs system of units and not ft-lb-s units, unless otherwise noted in the text. The gravitational conversion factor gc needed to use ft-lb-s units is not included in the equations. 

Our discussion of electromagnetic radiation uses the cgs system of units. 

Light beams are represented by electromagnetic waves that are described in a medium by four vector fields the electric field E r, t), the magnetic field H r, t), the electric displacement field D r,t), and B r,t) the magnetic induction field (or magnetic flux density). Throughout this chapter we will use bold symbols to denote vector quantities. All field vectors are functions of position and time. In a dielectric medium they satisfy a set of coupled partial differential equations known as Maxwell s equations. In the CGS system of units, they give... 

In the CGS system of units adopted through this chapter all the held quantities... 

Cgs system of units - A system of units based upon the centimeter, gram, and second. The cgs system has been supplanted by the International System (SI). 

In order to maintain historical continuity we have used the Gauss-cgs systems of units, used in the original papers of Ramsey. In this system cq = = I with a... 

The magnetic field strength inside a substance differs from the field strength of the applied field H (measured in the electromagnetic cgs system of units in vacuo) according to... 

Another system of units sometimes used in Eq. (2.2-1) is that where thefts is omitted and the force (F = mg) is given as lb , ft/s, which is called poundals. Then 1 lb acted on by gravity will give a force of 32.174 poundals(lb ft/s ). Or if I g mass is used, the force (F = mg) is expressed in terms of dynes (g - cm/s ). This is the centimeter-gram-second (cgs) systems of units. 

If Qed Cqx are taken as bulk concentrations in the solution, it is implied that equilibria are established for the approach steps from bulk to reacting sites. The dimensions of and Cqx are (length)" and it follows that ko and ko are in cm/sec if the cgs system of units is used. 

Table 1.2-11 deals with the relationship between CGS units and SI units, and lists those CGS units that were assigned special names. In the field of mechanics, the CGS system of units was built upon three quantities and their corresponding base units the centimeter, the gram, and the second. In the field of electricity and magnetism, units were expressed in terms of these three base units. Because this can be done in different ways, this led to the establishment of several different systems, for example the CGS electrostatic system, the CGS electromagnetic system, and the CGS Gaussian system. In those three systems, the system of quantities used... 

If the cgs system of units be used, both q> and 6 have the dimensions of radians per centimeter. They must be multiphed by 1800/ji to have the more common experimental units of degrees per decimeter. The most frequently encountered ways of expressing rotation data are in terms of the specific rotation [ ] and the molecular rotation [93] defined below ... 

The cohesive energy density is defined as the energy per unit volume, and the solubility parameter is the square root of that. In the cgs system of units, the cohesive energy density was measured as cal/cm, so the solubility parameter was (cal/cm ). In the current SI system used in this text, cohesive energy density is given in MPa, so the solubility parameter is MPa. Multiply the old (cal/cm ) value by 2.046 to convert to MPa. ... 

In the centimeter-gram-second (cgs) system of units, a statcoulomb is a unit of charge such that (1 statcoulombjV (1 cm) = 1 dyne, the CGS unit offeree. How many statcou-lombs are there in a coulomb ... 

A dyne (abbreviation dyn) is the unit of force in the cgs system of units, and is commonly used to express surface tensions. 1 N = 100,000 dyn. 

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