Physical quantities. Physical quantities and their units of measurement. Power in physics is a unit of measurement. What is i measured in?

Physical size is a physical property of a material object, process, physical phenomenon, characterized quantitatively.

Physical quantity value expressed by one or more numbers characterizing this physical quantity, indicating the unit of measurement.

The size of a physical quantity are the values of numbers appearing in the value of a physical quantity.

Units of measurement of physical quantities.

Unit of measurement of physical quantity is a quantity of fixed size that is assigned a numerical value equal to one. It is used for the quantitative expression of physical quantities homogeneous with it. A system of units of physical quantities is a set of basic and derived units based on a certain system of quantities.

Only a few systems of units have become widespread. In most cases, many countries use the metric system.

Basic units.

Measure a physical quantity - means to compare it with another similar physical quantity taken as a unit.

The length of an object is compared with a unit of length, the mass of a body with a unit of weight, etc. But if one researcher measures the length in fathoms and another in feet, it will be difficult for them to compare the two values. Therefore, all physical quantities throughout the world are usually measured in the same units. In 1963, the International System of Units SI (System international - SI) was adopted.

For each physical quantity in the system of units there must be a corresponding unit of measurement. Standard units is its physical implementation.

The length standard is meter- the distance between two strokes applied on a specially shaped rod made of an alloy of platinum and iridium.

Standard time serves as the duration of any regularly repeating process, for which the movement of the Earth around the Sun is chosen: the Earth makes one revolution per year. But the unit of time is taken not to be a year, but give me a sec.

For a unit speed take the speed of such uniform rectilinear motion at which the body moves 1 m in 1 s.

A separate unit of measurement is used for area, volume, length, etc. Each unit is determined when choosing a particular standard. But the system of units is much more convenient if only a few units are selected as the main ones, and the rest are determined through the main ones. For example, if the unit of length is a meter, then the unit of area will be a square meter, volume will be a cubic meter, speed will be a meter per second, etc.

Basic units The physical quantities in the International System of Units (SI) are: meter (m), kilogram (kg), second (s), ampere (A), kelvin (K), candela (cd) and mole (mol).

Basic SI units
Magnitude	Unit	Designation
Magnitude	Name	Russian	international



Electric current strength
Thermodynamic temperature
The power of light
Quantity of substance

There are also derived SI units that have their own names:

Derived SI units with their own names
	Unit		Derived unit expression
Magnitude	Name	Designation	Through other SI units	Through SI major and supplementary units


Pressure				m -1 ChkgChs -2
Energy, work, amount of heat				m 2 ChkgChs -2
Power, energy flow				m 2 ChkgChs -3
Amount of electricity, electric charge
Electrical voltage, electrical potential				m 2 ChkgChs -3 ChA -1
Electrical capacity				m -2 Chkg -1 Ch 4 Ch 2
Electrical resistance				m 2 ChkgChs -3 ChA -2
Electrical conductivity				m -2 Chkg -1 Ch 3 Ch 2
Magnetic induction flux				m 2 ChkgChs -2 ChA -1
Magnetic induction				kgHs -2 HA -1
Inductance				m 2 ChkgChs -2 ChA -2
Light flow
Illumination				m 2 ChkdChsr
Radioactive source activity	becquerel
Absorbed radiation dose

ANDmeasurements. To obtain an accurate, objective and easily reproducible description of a physical quantity, measurements are used. Without measurements, a physical quantity cannot be characterized quantitatively. Definitions such as “low” or “high” pressure, “low” or “high” temperature reflect only subjective opinions and do not contain comparisons with reference values. When measuring a physical quantity, a certain numerical value is assigned to it.

Measurements are carried out using measuring instruments. There are quite a large number of measuring instruments and devices, from the simplest to the most complex. For example, length is measured with a ruler or tape measure, temperature with a thermometer, width with calipers.

Measuring instruments are classified: by the method of presenting information (displaying or recording), by the method of measurement (direct action and comparison), by the form of presentation of readings (analog and digital), etc.

The following parameters are typical for measuring instruments:

Measuring range- the range of values of the measured quantity for which the device is designed during its normal operation (with a given measurement accuracy).

Sensitivity threshold- the minimum (threshold) value of the measured value, distinguished by the device.

Sensitivity- connects the value of the measured parameter and the corresponding change in the instrument readings.

Accuracy- the ability of the device to indicate the true value of the measured indicator.

Stability- the ability of the device to maintain a given measurement accuracy for a certain time after calibration.

The international designation for watts is W, and in Russian it is “W”. Now this energy measurement parameter is widely used in various mechanisms - from household appliances to complex technical structures.

Story

The unit of measurement watt was named after the Scottish engineer who created a steam engine, the model of which he modified from Newcomen's invention.

Thus, it was adopted at the second congress of the scientific association in Great Britain in 1882. Until then, most energy calculations used horsepower, one metric unit of which equals approximately 735 watts.

Watt as a quantity in physics

To better understand what is measured in watts, you need to brush up on your school physics lessons and remember the definition of energy. A physical quantity that uses the international SI unit joule (J) and is called energy. It is used as a general measure of the effectiveness of various thermal processes or interactions between objects and other phenomena occurring with matter - in science, nature, technology, etc.

That's what is measured in watts - power that determines how much energy different objects consume or emit. The speed of its transmission through objects and transformation of one form into another is also calculated. In other words, power, defined in watts, is equal to 1 unit of energy divided by 1 unit of time - a second:

1W=1J/1sec

Volts and watts

What is the difference between a volt and a watt? Voltage is calculated in volts. Let's say the voltage of the power source - battery, accumulator or network - must be equal to or deviate slightly (in%) from the voltage that is installed on the device - a lamp or complex electronic equipment.

What is measured in watts? The answer here is already clear - this is power, which can be calculated as energy consumed, for example, when choosing a kettle - it will heat up faster, but will consume more electricity. Or given the output power of, say, a speaker or amplifier, the higher the power, the wider the range and louder the sound. Watt is also indicated in internal combustion engines - cars, motorcycles, trimmers and other mechanisms. However, the "horsepower" measurement is often used for such engines in other countries.

Power of electrical appliances

The power of household appliances is measured in watts, which is usually specified by the manufacturer. Some devices, such as lamps, can set power limits so that if the cartridge becomes very hot, they do not fail. Which will limit the period of use. Typically, such problems arise with incandescent lamps. In Europe, for example, the use of these lamps was limited due to their high power.

LED lamps consume much less electricity, while the brightness of such a lamp is not inferior to incandescent lamps. For example, with an average brightness of 800 lumens, the energy consumption of an incandescent lamp, measured in watts, will be 60, and an LED lamp will be from 10 to 15 watts, which is 4-6 times less. The power of the fluorescent lamp is 13-15 watts. So, although the cost is higher, LED or fluorescent lighting is becoming more common because it lasts longer and is energy efficient.

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Books

Hydraulics. Textbook and workshop for academic bachelor's degree, V.A. Kudinov. The textbook outlines the basic physical and mechanical properties of liquids, issues of hydrostatics and hydrodynamics, provides the basics of the theory of hydrodynamic similarity and mathematical modeling...
Hydraulics 4th ed., trans. and additional Textbook and workshop for academic bachelor's degree, Eduard Mikhailovich Kartashov. The textbook outlines the basic physical and mechanical properties of liquids, issues of hydrostatics and hydrodynamics, provides the basics of the theory of hydrodynamic similarity and mathematical modeling...

Power, heat flow

The method for setting temperature values is the temperature scale. Several temperature scales are known.

Kelvin scale(named after the English physicist W. Thomson, Lord Kelvin).
Unit designation: K(not “degree Kelvin” and not °K).
1 K = 1/273.16 - part of the thermodynamic temperature of the triple point of water, corresponding to the thermodynamic equilibrium of a system consisting of ice, water and steam.
Celsius(named after the Swedish astronomer and physicist A. Celsius).
Unit designation: °C .
In this scale, the melting temperature of ice at normal pressure is taken to be 0°C, and the boiling point of water is 100°C.
The Kelvin and Celsius scales are related by the equation: t (°C) = T (K) - 273.15.
Fahrenheit(D. G. Fahrenheit - German physicist).
Unit symbol: °F. Widely used, particularly in the USA.
The Fahrenheit scale and the Celsius scale are related: t (°F) = 1.8 · t (°C) + 32°C. In absolute value, 1 (°F) = 1 (°C).
Reaumur scale(named after the French physicist R.A. Reaumur).
Designation: °R and °r.
This scale is almost out of use.
Relation to degrees Celsius: t (°R) = 0.8 t (°C).
Rankin Scale (Rankine)- named after the Scottish engineer and physicist W. J. Rankin.
Designation: °R (sometimes: °Rank).
The scale is also used in the USA.
Temperature on the Rankine scale is related to temperature on the Kelvin scale: t (°R) = 9/5 · T (K).

Basic temperature indicators in units of measurement of different scales:

The SI unit of measurement is meter (m).

Non-system unit: Angstrom (Å). 1Å = 1·10-10 m.
Inch(from Dutch duim - thumb); inch; in; ´´; 1´ = 25.4 mm.
Hand(English hand - hand); 1 hand = 101.6 mm.
Link(English link - link); 1 li = 201.168 mm.
Span(English span - span, scope); 1 span = 228.6 mm.
Foot(English foot - leg, feet - feet); 1 ft = 304.8 mm.
Yard(English yard - yard, corral); 1 yd = 914.4 mm.
Fat, face(English fathom - measure of length (= 6 ft), or measure of volume of wood (= 216 ft 3), or mountain measure of area (= 36 ft 2), or fathom (Ft)); fath or fth or Ft or ƒfm; 1 Ft = 1.8288 m.
Cheyne(English chain - chain); 1 ch = 66 ft = 22 yd = = 20.117 m.
Furlong(eng. furlong) - 1 fur = 220 yd = 1/8 mile.
mile(English mile; international). 1 ml (mi, MI) = 5280 ft = 1760 yd = 1609.344 m.

The SI unit is m2.

Square foot; 1 ft 2 (also sq ft) = 929.03 cm 2.
Square inch; 1 in 2 (sq in) = 645.16 mm 2.
Square fathom (fesom); 1 fath 2 (ft 2; Ft 2; sq Ft) = 3.34451 m 2.
Square Yard; 1 yd 2 (sq yd)= 0.836127 m 2 .

Sq (square) - square.

The SI unit is m3.

Cubic foot; 1 ft 3 (also cu ft) = 28.3169 dm 3.
Cubic Fathom; 1 fath 3 (fth 3; Ft 3; cu Ft) = 6.11644 m 3.
Cubic Yard; 1 yd 3 (cu yd) = 0.764555 m 3.
Cubic inch; 1 in 3 (cu in) = 16.3871 cm 3.
Bushel (UK); 1 bu (uk, also UK) = 36.3687 dm 3.
Bushel (USA); 1 bu (us, also US) = 35.2391 dm 3.
Gallon (UK); 1 gal (uk, also UK) = 4.54609 dm 3.
Gallon liquid (USA); 1 gal (us, also US) = 3.78541 dm 3.
Gallon dry (USA); 1 gal dry (us, also US) = 4.40488 dm 3.
Jill (gill); 1 gi = 0.12 l (US), 0.14 l (UK).
Barrel (USA); 1bbl = 0.16 m3.

UK - United Kingdom - United Kingdom (Great Britain); US - United Stats (USA).

Specific volume

The SI unit of measurement is m 3 /kg.

ft 3/lb; 1 ft3 / lb = 62.428 dm 3 / kg .

The SI unit of measurement is kg.

Pound (trading) (English libra, pound - weighing, pound); 1 lb = 453.592 g; lbs - pounds. In the system of old Russian measures 1 lb = 409.512 g.
Gran (English grain - grain, grain, grain); 1 gr = 64.799 mg.
Stone (eng. stone - stone); 1 st = 14 lb = 6.350 kg.

Density, incl. bulk

The SI unit of measurement is kg/m3.

lb/ft 3 ; 1 lb/ft 3 = 16.0185 kg/m 3.

Linear density

The SI unit is kg/m.

lb/ft; 1 lb/ft = 1.48816 kg/m
Pound/Yard; 1 lb / yd = 0.496055 kg/m

Surface density

The SI unit is kg/m2.

lb/ft 2 ; 1 lb / ft 2 (also lb / sq ft - pound per square foot) = 4.88249 kg/m2.

Linear speed

The SI unit is m/s.

ft/h; 1 ft/h = 0.3048 m/h.
ft/s; 1 ft/s = 0.3048 m/s.

The SI unit is m/s2.

ft/s 2 ; 1 ft/s2 = 0.3048 m/s2.

Mass flow

The SI unit is kg/s.

lb/h; 1 lb/h = 0.453592 kg/h.
lb/s; 1 lb/s = 0.453592 kg/s.

Volume flow

The SI unit of measurement is m 3 /s.

ft 3 /min; 1 ft 3 / min = 28.3168 dm 3 / min.
Yard 3/min; 1 yd 3 / min = 0.764555 dm 3 / min.
Gpm; 1 gal/min (also GPM - gallon per min) = 3.78541 dm 3 /min.

Specific volume flow

GPM/(sq·ft) - gallon (G) per (P) minute (M)/(square (sq) · foot (ft)) - gallons per minute per square foot;
1 GPM/(sq ft) = 2445 l/(m 2 h) 1 l/(m 2 h) = 10 -3 m/h.
gpd - gallons per day - gallons per day (day); 1 gpd = 0.1577 dm 3 /h.
gpm - gallons per minute - gallons per minute; 1 gpm = 0.0026 dm 3 /min.
gps - gallons per second - gallons per second; 1 gps = 438 10 -6 dm 3 /s.

Consumption of sorbate (for example, Cl 2) when filtering through a layer of sorbent (for example, active carbon)

Gals/cu ft (gal/ft 3) - gallons/cubic foot (gallons per cubic foot); 1 Gals/cu ft = 0.13365 dm 3 per 1 dm 3 of sorbent.

The SI unit of measurement is N.

Pound-force; 1 lbf - 4.44822 N. (An analogue of the name of the unit of measurement: kilogram-force, kgf. 1 kgf = = 9.80665 N (exact). 1 lbf = 0.453592 (kg) 9.80665 N = = 4 .44822 N 1N=1 kg m/s 2
Poundal (English: poundal); 1 pdl = 0.138255 N. (Poundall is the force that gives a mass of one pound an acceleration of 1 ft/s 2, lb ft/ s 2.)

Specific gravity

The SI unit of measurement is N/m 3 .

lbf/ft 3 ; 1 lbf/ft 3 = 157.087 N/m 3.
Poundal/ft 3 ; 1 pdl/ft 3 = 4.87985 N/m 3.

SI unit of measurement - Pa, multiple units: MPa, kPa.

In their work, specialists continue to use outdated, canceled or previously optionally accepted units of pressure measurement: kgf/cm 2; bar; atm. (physical atmosphere); at(technical atmosphere); ata; ati; m water Art.; mmHg st; torr.

The following concepts are used: “absolute pressure”, “excess pressure”. There are errors when converting some pressure units into Pa and its multiples. It must be taken into account that 1 kgf/cm 2 is equal to 98066.5 Pa (exactly), that is, for small (up to approximately 14 kgf/cm 2) pressures with sufficient accuracy for work the following can be accepted: 1 Pa = 1 kg/(m s 2) = 1 N/m 2. 1 kgf/cm 2 ≈ 105 Pa = 0.1 MPa. But already at medium and high pressures: 24 kgf/cm 2 ≈ 23.5 105 Pa = 2.35 MPa; 40 kgf/cm2 ≈ 39 · 105 Pa = 3.9 MPa; 100 kgf/cm 2 ≈ 98 105 Pa = 9.8 MPa etc.

Ratios:

1 atm (physical) ≈ 101325 Pa ≈ 1.013 105 Pa ≈ ≈ 0.1 MPa.
1 at (technical) = 1 kgf/cm 2 = 980066.5 Pa ≈ 105 Pa ≈ 0.09806 MPa ≈ 0.1 MPa.
0.1 MPa ≈ 760 mm Hg. Art. ≈ 10 m water. Art. ≈ 1 bar.
1 Torr (tor) = 1 mm Hg. Art.
lbf/in 2 ; 1 lbf/in 2 = 6.89476 kPa (see below: PSI).
lbf/ft 2 ; 1 lbf/ft 2 = 47.8803 Pa.
lbf/yd 2 ; 1 lbf/yd 2 = 5.32003 Pa.
Poundal/ft 2 ; 1 pdl/ft 2 = 1.48816 Pa.
Foot water column; 1 ft H 2 O = 2.98907 kPa.
Inch of water column; 1 in H 2 O = 249.089 Pa.
Inch of mercury; 1 in Hg = 3.38639 kPa.
PSI (also psi) - pounds (P) per square (S) inch (I) - pounds per square inch; 1 PSI = 1 lbƒ/in 2 = 6.89476 kPa.

Sometimes in the literature the designation of the pressure unit lb/in 2 is found - this unit takes into account not lbƒ (pound-force), but lb (pound-mass). Therefore, in numerical terms, 1 lb/ in 2 is slightly different from 1 lbf/ in 2, since when determining 1 lbƒ it was taken into account: g = 9.80665 m/s 2 (at the latitude of London). 1 lb/in 2 = 0.454592 kg/(2.54 cm) 2 = 0.07046 kg/cm 2 = 7.046 kPa. Calculation of 1 lbƒ - see above. 1 lbf/in 2 = 4.44822 N/(2.54 cm) 2 = 4.44822 kg m/ (2.54 0.01 m) 2 s 2 = 6894.754 kg/ (m s 2) = 6894.754 Pa ≈ 6.895 kPa.

For practical calculations we can assume: 1 lbf/in 2 ≈ 1 lb/in 2 ≈ 7 kPa. But, in fact, equality is illegal, just like 1 lbƒ = 1 lb, 1 kgf = 1 kg. PSIg (psig) - same as PSI, but indicates gauge pressure; PSIa (psia) - the same as PSI, but emphasizes: absolute pressure; a - absolute, g - gauge (measure, size).

Water pressure

The SI unit of measurement is m.

Head in feet (feet-head); 1 ft hd = 0.3048 m

Pressure loss during filtration

PSI/ft - pounds (P) per square (S) inch (I)/foot (ft) - pounds per square inch/foot; 1 PSI/ft = 22.62 kPa per 1 m of filter layer.

SI unit of measurement - Joule(named after the English physicist J.P. Joule).

1 J - mechanical work of force 1 N when moving a body over a distance of 1 m.
Newton (N) is the SI unit of force and weight; 1 Н is equal to the force imparting an acceleration of 1 m 2 /s to a body weighing 1 kg in the direction of the force. 1 J = 1 N m.

In heating engineering, they continue to use the abolished unit of measurement of the amount of heat - calorie (cal).

1 J (J) = 0.23885 cal. 1 kJ = 0.2388 kcal.
1 lbf ft (lbf ft) = 1.35582 J.
1 pdl ft (poundal feet) = 42.1401 mJ.
1 Btu (British Heat Unit) = 1.05506 kJ (1 kJ = 0.2388 kcal).
1 Therm (British large calorie) = 1 10 -5 Btu.

POWER, HEAT FLOW

SI unit of measurement is Watt (W)- named after the English inventor J. Watt - mechanical power at which 1 J of work is performed in 1 s, or a heat flux equivalent to 1 W of mechanical power.

1 W (W) = 1 J/s = 0.859985 kcal/h (kcal / h).
1 lbf ft/s (lbf ft/s) = 1.33582 W.
1 lbf ft/min (lbf ft/min) = 22.597 mW.
1 lbf ft/h (lbf ft/h) = 376.616 µW.
1 pdl ft/s (poundal feet/s) = 42.1401 mW.
1 hp (British horsepower/s) = 745.7 W.
1 Btu/s (British Heat Unit/s) = 1055.06 W.
1 Btu/h (British Heat Unit/h) = 0.293067 W.

Surface heat flux density

The SI unit is W/m2.

1 W/m2 (W/m2) = 0.859985 kcal/(m2 h) (kcal/(m2 h)).
1 Btu/(ft 2 h) = 2.69 kcal/(m 2 h) = 3.1546 kW/m 2.

Dynamic viscosity (viscosity coefficient), η.

SI unit - Pa s. 1 Pa s = 1 N s/m2;
non-systemic unit - poise (P). 1 P = 1 dyne s/m 2 = 0.1 Pa s.

Dina (dyn) - (from the Greek dynamic - strength). 1 dyne = 10 -5 N = 1 g cm/s 2 = 1.02 10 -6 kgf.
1 lbf h/ft 2 (lbf h/ft 2) = 172.369 kPa s.
1 lbf s / ft 2 (lbf s/ft 2) = 47.8803 Pa s.
1 pdl s / ft 2 (poundal-s/ft 2) = 1.48816 Pa s.
1 slug /(ft s) = 47.8803 Pa s. Slug (slug) is a technical unit of mass in the English system of measures.

Kinematic viscosity, ν.

Unit of measurement in SI - m 2 /s; The unit cm 2 /s is called “Stokes” (named after the English physicist and mathematician J. G. Stokes).

Kinematic and dynamic viscosity are related by the equality: ν = η / ρ, where ρ is density, g/cm 3 .

1 m 2 /s = Stokes / 104.
1 ft 2 /h (ft 2 /h) = 25.8064 mm 2 /s.
1 ft 2 /s (ft 2 /s) = 929.030 cm 2 /s.

The SI unit of magnetic field strength is A/m(Ammeter). Ampere (A) is the surname of the French physicist A.M. Ampere.

Previously, the Oersted unit (E) was used - named after the Danish physicist H.K. Oersted.
1 A/m (A/m, At/m) = 0.0125663 Oe (Oe)

The resistance to crushing and abrasion of mineral filter materials and, in general, of all minerals and rocks is indirectly determined using the Mohs scale (F. Mohs - German mineralogist).

In this scale, numbers in ascending order designate minerals arranged in such a way that each subsequent one is capable of leaving a scratch on the previous one. The extreme substances on the Mohs scale are talc (hardness unit 1, the softest) and diamond (10, the hardest).

Hardness 1-2.5 (drawn with a fingernail): volskonkoite, vermiculite, halite, gypsum, glauconite, graphite, clay materials, pyrolusite, talc, etc.
Hardness >2.5-4.5 (not drawn with a fingernail, but drawn with glass): anhydrite, aragonite, barite, glauconite, dolomite, calcite, magnesite, muscovite, siderite, chalcopyrite, chabazite, etc.
Hardness >4.5-5.5 (not drawn with glass, but drawn with a steel knife): apatite, vernadite, nepheline, pyrolusite, chabazite, etc.
Hardness >5.5-7.0 (not drawn with a steel knife, but drawn with quartz): vernadite, garnet, ilmenite, magnetite, pyrite, feldspars, etc.
Hardness >7.0 (not marked with quartz): diamond, garnets, corundum, etc.

The hardness of minerals and rocks can also be determined using the Knoop scale (A. Knoop - German mineralogist). In this scale, values are determined by the size of the imprint left on the mineral when a diamond pyramid is pressed into its sample under a certain load.

Ratios of indicators on the Mohs (M) and Knoop (K) scales:

SI unit of measurement - Bq(Becquerel, named after the French physicist A.A. Becquerel).

Bq (Bq) is a unit of activity of a nuclide in a radioactive source (isotope activity). 1 Bq is equal to the activity of a nuclide, at which one decay event occurs in 1 s.

Radioactivity concentration: Bq/m 3 or Bq/l.

Activity is the number of radioactive decays per unit time. The activity per unit mass is called specific.

Curie (Ku, Ci, Cu) is a unit of activity of a nuclide in a radioactive source (isotope activity). 1 Ku is the activity of an isotope in which 3.7000 · 1010 decay events occur in 1 s. 1 Ku = 3.7000 · 1010 Bq.
Rutherford (Рд, Rd) is an obsolete unit of activity of nuclides (isotopes) in radioactive sources, named after the English physicist E. Rutherford. 1 Rd = 1 106 Bq = 1/37000 Ci.

Radiation dose

Radiation dose is the energy of ionizing radiation absorbed by the irradiated substance and calculated per unit of its mass (absorbed dose). The dose accumulates over time of exposure. Dose rate ≡ Dose/time.

SI unit of absorbed dose - Gray (Gy, Gy). The extrasystemic unit is Rad, corresponding to the radiation energy of 100 erg absorbed by a substance weighing 1 g.

Erg (erg - from the Greek: ergon - work) is a unit of work and energy in the non-recommended GHS system.

1 erg = 10 -7 J = 1.02 10 -8 kgf m = 2.39 10 -8 cal = 2.78 10 -14 kW h.
1 rad = 10 -2 Gr.
1 rad (rad) = 100 erg/g = 0.01 Gy = 2.388 · 10 -6 cal/g = 10 -2 J/kg.

Kerma (abbreviated English: kinetic energy released in matter) - kinetic energy released in matter, measured in grays.

The equivalent dose is determined by comparing the nuclide radiation with X-ray radiation. The radiation quality factor (K) shows how many times the radiation hazard in the case of chronic human exposure (in relatively small doses) for a given type of radiation is greater than in the case of X-ray radiation at the same absorbed dose. For X-ray and γ-radiation K = 1. For all other types of radiation K is established according to radiobiological data.

Deq = Dpogl · K.

SI unit of absorbed dose - 1 Sv(Sievert) = 1 J/kg = 102 rem.

BER (rem, ri - until 1963 was defined as the biological equivalent of an x-ray) - a unit of equivalent dose of ionizing radiation.
X-ray (P, R) - unit of measurement, exposure dose of X-ray and γ-radiation. 1 P = 2.58 10 -4 C/kg.
Coulomb (C) is an SI unit, amount of electricity, electric charge. 1 rem = 0.01 J/kg.

Equivalent dose rate - Sv/s.

Permeability of porous media (including rocks and minerals)

Darcy (D) - named after the French engineer A. Darcy, darsy (D) · 1 D = 1.01972 µm 2.

1 D is the permeability of such a porous medium, when filtering through a sample with an area of 1 cm 2, a thickness of 1 cm and a pressure drop of 0.1 MPa, the flow rate of a liquid with a viscosity of 1 cP is equal to 1 cm 3 /s.

Sizes of particles, grains (granules) of filter materials according to SI and standards of other countries

In the USA, Canada, Great Britain, Japan, France and Germany, grain sizes are estimated in meshes (eng. mesh - hole, cell, network), that is, by the number (number) of holes per inch of the finest sieve through which they can pass grains And the effective grain diameter is the hole size in microns. In recent years, US and UK mesh systems have been used more frequently.

The relationship between the units of measurement of grain sizes (granules) of filter materials according to SI and standards of other countries:

Mass fraction

Mass fraction shows what mass amount of a substance is contained in 100 parts by mass of a solution. Units of measurement: fractions of a unit; interest (%); ppm (‰); parts per million (ppm).

Solution concentration and solubility

The concentration of a solution must be distinguished from solubility - the concentration of a saturated solution, which is expressed by the mass amount of a substance in 100 parts by mass of a solvent (for example, g/100 g).

Volume concentration

Volume concentration is the mass amount of a dissolved substance in a certain volume of solution (for example: mg/l, g/m3).

Molar concentration

Molar concentration is the number of moles of a given substance dissolved in a certain volume of solution (mol/m3, mmol/l, µmol/ml).

Molal concentration

Molal concentration is the number of moles of a substance contained in 1000 g of solvent (mol/kg).

Normal solution

A solution is called normal if it contains one equivalent of a substance per unit volume, expressed in mass units: 1H = 1 mg eq/l = 1 mmol/l (indicating the equivalent of a specific substance).

Equivalent

The equivalent is equal to the ratio of the part of the mass of an element (substance) that adds or replaces one atomic mass of hydrogen or half the atomic mass of oxygen in a chemical compound to 1/12 of the mass of carbon 12. Thus, the equivalent of an acid is equal to its molecular weight, expressed in grams, divided by the basicity (the number of hydrogen ions); base equivalent - molecular weight divided by acidity (the number of hydrogen ions, and for inorganic bases - divided by the number of hydroxyl groups); salt equivalent - molecular weight divided by the sum of charges (valence of cations or anions); the equivalent of a compound participating in redox reactions is the quotient of the molecular weight of the compound divided by the number of electrons accepted (donated) by an atom of the reducing (oxidizing) element.

Relationships between units of measurement of the concentration of solutions
(Formula for transition from one expression of solution concentrations to another):

Accepted designations:

ρ - solution density, g/cm 3 ;
m is the molecular weight of the dissolved substance, g/mol;
E is the equivalent mass of a solute, that is, the amount of substance in grams that interacts in a given reaction with one gram of hydrogen or corresponds to the transition of one electron.

According to GOST 8.417-2002 The unit of quantity of a substance is established: mole, multiples and submultiples ( kmol, mmol, µmol).

The SI unit of measurement for hardness is mmol/l; µmol/l.

In different countries, the abolished units for measuring water hardness often continue to be used:

Russia and CIS countries - mEq/l, mcg-eq/l, g-eq/m 3 ;
Germany, Austria, Denmark and some other countries of the Germanic group of languages - 1 German degree - (Н° - Harte - hardness) ≡ 1 part CaO/100 thousand parts water ≡ 10 mg CaO/l ≡ 7.14 mg MgO/ l ≡ 17.9 mg CaCO 3 /l ≡ 28.9 mg Ca(HCO 3) 2 /l ≡ 15.1 mg MgCO 3 /l ≡ 0.357 mmol/l.
1 French degree ≡ 1 hour CaCO 3 /100 thousand parts water ≡ 10 mg CaCO 3 /l ≡ 5.2 mg CaO/l ≡ 0.2 mmol/l.
1 English degree ≡ 1 grain/1 gallon of water ≡ 1 part CaCO 3 /70 thousand parts water ≡ 0.0648 g CaCO 3 /4.546 l ≡ 100 mg CaCO3 /7 l ≡ 7.42 mg CaO/l ≡ 0.285 mmol /l. Sometimes the English degree of hardness is denoted Clark.
1 American degree ≡ 1 part CaCO 3 /1 million part water ≡ 1 mg CaCO 3 /l ≡ 0.52 mg CaO/l ≡ 0.02 mmol/l.

Here: part - part; the conversion of degrees into their corresponding amounts of CaO, MgO, CaCO 3, Ca(HCO 3) 2, MgCO 3 is shown as examples mainly for German degrees; Dimensions of degrees are tied to calcium-containing compounds, since calcium in the composition of hardness ions is usually 75-95%, in rare cases - 40-60%. Numbers are generally rounded to the second decimal place.

The relationship between units of water hardness:

1 mmol/l = 1 mg eq/l = 2.80°H (German degrees) = 5.00 French degrees = 3.51 English degrees = 50.04 American degrees.

A new unit of measurement of water hardness is the Russian degree of hardness - °Zh, defined as the concentration of an alkaline earth element (mainly Ca 2+ and Mg 2+), numerically equal to ½ its mole in mg/dm 3 (g/m 3).

Alkalinity units are mmol, µmol.

The SI unit of electrical conductivity is µS/cm.

The electrical conductivity of solutions and its inverse electrical resistance characterize the mineralization of solutions, but only the presence of ions. When measuring electrical conductivity, non-ionic organic substances, neutral suspended impurities, interference that distorts the results - gases, etc. cannot be taken into account. It is impossible by calculation to accurately find the correspondence between the values of specific electrical conductivity and the dry residue or even the sum of all separately determined substances of the solution, since in In natural water, different ions have different electrical conductivity, which simultaneously depends on the salinity of the solution and its temperature. To establish such a dependence, it is necessary to experimentally establish the relationship between these quantities for each specific object several times a year.

1 µS/cm = 1 MΩ cm; 1 S/m = 1 Ohm m.

For pure solutions of sodium chloride (NaCl) in distillate, the approximate ratio is:

1 µS/cm ≈ 0.5 mg NaCl/l.

The same ratio (approximately), taking into account the above reservations, can be accepted for most natural waters with mineralization up to 500 mg/l (all salts are converted to NaCl).

When mineralization of natural water is 0.8-1.5 g/l, you can take:

1 µS/cm ≈ 0.65 mg salts/l,

and with mineralization - 3-5 g/l:

1 µS/cm ≈ 0.8 mg salts/l.

Content of suspended impurities in water, transparency and turbidity of water

Water turbidity is expressed in units:

JTU (Jackson Turbidity Unit) - Jackson turbidity unit;
FTU (Formasin Turbidity Unit, also designated EMF) - unit of turbidity for formazin;
NTU (Nephelometric Turbidity Unit) - nephelometric turbidity unit.

It is impossible to give an exact ratio of turbidity units to suspended solids content. For each series of determinations, it is necessary to construct a calibration graph that allows you to determine the turbidity of the analyzed water in comparison with the control sample.

As a rough guide: 1 mg/l (suspended solids) ≡ 1-5 NTU units.

If the clouding mixture (diatomaceous earth) has a particle size of 325 mesh, then: 10 units. NTU ≡ 4 units JTU.

GOST 3351-74 and SanPiN 2.1.4.1074-01 equate to 1.5 units. NTU (or 1.5 mg/l for silica or kaolin) 2.6 units. FTU (EMF).

The relationship between font transparency and haze:

The relationship between transparency along the “cross” (in cm) and turbidity (in mg/l):

The SI unit of measurement is mg/l, g/m3, μg/l.

In the USA and some other countries, mineralization is expressed in relative units (sometimes in grains per gallon, gr/gal):

ppm (parts per million) - part per million (1 · 10 -6) of a unit; sometimes ppm (parts per mille) also means a thousandth (1 · 10 -3) of a unit;
ppb - (parts per billion) billionth (billionth) fraction (1 · 10 -9) of a unit;
ppt - (parts per trillion) trillionth part (1 · 10 -12) of a unit;
‰ - ppm (also used in Russia) - thousandth (1 · 10 -3) of a unit.

The relationship between the units of measurement of mineralization: 1 mg/l = 1 ppm = 1 · 10 3 ppb = 1 · 10 6 ppt = 1 · 10 -3 ‰ = 1 · 10 -4%; 1 gr/gal = 17.1 ppm = 17.1 mg/l = 0.142 lb/1000 gal.

For measuring the salinity of salt waters, brines and salinity of condensates It is more correct to use units: mg/kg. In laboratories, water samples are measured by volume rather than by mass, so in most cases it is advisable to refer the amount of impurities to a liter. But for large or very small values of mineralization the error will be sensitive.

According to SI, volume is measured in dm 3, but measurement is also allowed in liters, because 1 l = 1.000028 dm 3. Since 1964 1 l is equal to 1 dm 3 (exactly).

For salt waters and brines salinity units are sometimes used in degrees Baume(for mineralization >50 g/kg):

1°Be corresponds to a solution concentration equal to 1% in terms of NaCl.
1% NaCl = 10 g NaCl/kg.

Dry and calcined residue

Dry and calcined residues are measured in mg/l. The dry residue does not fully characterize the mineralization of the solution, since the conditions for its determination (boiling, drying the solid residue in an oven at a temperature of 102-110 ° C to constant weight) distort the result: in particular, part of the bicarbonates (conventionally accepted - half) decomposes and volatilizes in the form of CO 2.

Decimal multiples and submultiples of quantities

Decimal multiples and submultiple units of measurement of quantities, as well as their names and designations, should be formed using the factors and prefixes given in the table:

(based on materials from the site https://aqua-therm.ru/).

Consider the physical record m=4kg. In this formula "m"- designation of a physical quantity (mass), "4" - numerical value or magnitude, "kg"- unit of measurement of a given physical quantity.

There are different types of quantities. Here are two examples:
1) The distance between points, the lengths of segments, broken lines - these are quantities of the same kind. They are expressed in centimeters, meters, kilometers, etc.
2) The durations of time intervals are also quantities of the same kind. They are expressed in seconds, minutes, hours, etc.

Quantities of the same kind can be compared and added:

BUT! It makes no sense to ask what is greater: 1 meter or 1 hour, and you cannot add 1 meter to 30 seconds. The duration of time intervals and distance are quantities of different kinds. They cannot be compared or added together.

Quantities can be multiplied by positive numbers and zero.

Taking any value e per unit of measurement, you can use it to measure any other quantity A same kind. As a result of the measurement we obtain that A=x e, where x is a number. This number x is called the numerical value of the quantity A with unit of measurement e.

There are dimensionless physical quantities. They do not have units of measurement, that is, they are not measured in anything. For example, friction coefficient.

What is SI?

According to data from Professor Peter Cumpson and Dr Naoko Sano from the University of Newcastle, published in the journal Metrology, the standard kilogram gains on average about 50 micrograms per hundred years, which ultimately can significantly affect many physical quantities.

The kilogram is the only SI unit that is still defined using a standard. All other measures (meter, second, degree, ampere, etc.) can be determined with the necessary accuracy in a physical laboratory. The kilogram is included in the definition of other quantities, for example, the unit of force is the newton, which is defined as a force that changes the speed of a body weighing 1 kg by 1 m/s in 1 second in the direction of the force. Other physical quantities depend on the value of Newton, so in the end the chain can lead to a change in the value of many physical units.

The most important kilogram is a cylinder with a diameter and height of 39 mm, consisting of an alloy of platinum and iridium (90% platinum and 10% iridium). It was cast in 1889 and is kept in a safe at the International Bureau of Weights and Measures in Sèvres near Paris. The kilogram was originally defined as the mass of one cubic decimeter (liter) of pure water at a temperature of 4 °C and standard atmospheric pressure at sea level.

From the standard kilogram, 40 exact copies were initially made, which were distributed throughout the world. Two of them are located in Russia, at the All-Russian Research Institute of Metrology named after. Mendeleev. Later another series of replicas was cast. Platinum was chosen as the base material for the standard because it has high oxidation resistance, high density and low magnetic susceptibility. The standard and its replicas are used to standardize mass in a variety of industries. Including where micrograms are significant.

Physicists believe that the weight fluctuations were the result of atmospheric pollution and changes in the chemical composition of the cylinder surfaces. Despite the fact that the standard and its replicas are stored in special conditions, this does not save the metal from interaction with the environment. The exact weight of the kilogram was determined using X-ray photoelectron spectroscopy. It turned out that the kilogram “gained” by almost 100 micrograms.

At the same time, copies of the standard differed from the original from the very beginning and their weight also changes differently. Thus, the main American kilogram initially weighed 39 micrograms less than the standard, and a check in 1948 showed that it had increased by 20 micrograms. The other American copy, on the contrary, is losing weight. In 1889, kilogram number 4 (K4) weighed 75 mcg less than the standard, and in 1989 it was already 106 mcg.