Page 40 - Appplied Mathematics for the Petroleum and Other Industries, 5th Edition

300 GLOSSARY

ohm (Ω) n: the SI unit for electrical resistance. power. This ratio measures how effectively power is being
delivered and used.
Ohm’s law n: a basic law of electrical behavior, which
states that the strength or intensity of an unvarying elec- process variable (PV) n: the quantity of the process
trical current is directly proportional to the voltage and under consideration; this variable may be pressure, tem-
inversely proportional to the resistance of the current. perature, level, flow, density, or other characteristics of
The formula for Ohm’s law is: V = IR, where V stands for the process that can be measured.
voltage, I stands for current, and R stands for resistance. product n: the result obtained by multiplying one num-
operation key n: a key on a computer or calculator that ber by another.
allows the user to enter a mathematical operator (such proportion n: a relation of equality between two ratios.
as a plus sign, minus sign, multiplication sign, division
sign, or other signs) into the display.
ordinate n: the vertical coordinate of a point in a plane ob- quadrant n: one-fourth of a circle, or 90° of a circle.
tained by measuring parallel to the y-axis. Compare abscissa. quantity n: a property that can exist in a range of mag-
orifice n: in gas measurement, a precisely drilled hole of nitudes and multitudes.
a given size in a flat metal plate. quotient n: the result obtained by division.

pascal (Pa) n: the SI unit for measuring pressure, equal radial line n: a straight line that begins at the center of
2
to 1 N/m . the circle and radiates outward from the center.
percent n: a proportion of an amount in hundredths. rate n: in percentage problems, the desired percentage
The symbol for percent is % and expresses quantity in of the base.
relation to a whole. ratio n: a proportional relationship between two numbers
percentage n: the product of the rate times the base when or quantities.
calculating percent. reactive power n: the value of the power in an electric
perimeter n: the total distance of all the sides of a circuit obtained by multiplying the effective value of
polygon. the current in amperes, the effective value of the voltage
in volts, and the sine of the angular phase difference
physical quantity n: a quantity that has dimensions and between current and voltage.
can be measured, such as length, mass (weight), and time.
real power n: the component of apparent power that
pie chart n: See circle graph.
represents true work. It is represented in watts and equals
plane figure n: a figure that only has two dimensions. volt-amperes multiplied by the power factor.
potential n: See electromotive force and voltage. reciprocal n: a number related to another number by the
fact that the product of the two numbers is 1.
potential difference n: See electromotive force and voltage.
remainder n: the number that represents the results or
pound per square inch (psi) n: in the English system answer to a subtraction problem.
of measurement, the most often used unit of pressure.
resistance (R) n: opposition to the flow of direct current
pound per square inch absolute (psia) n: in the English caused by a particular material or device. Resistance is
system of measurement, the unit of pressure for absolute equal to the voltage drop across the circuit divided by
pressure, which signifies the total pressure measured from the current through the circuit.
an absolute vacuum. Absolute pressure equals the sum of
Petroleum Extension-The University of Texas at Austin
the gauge pressure and the atmospheric pressure, because right triangle n: a triangle that contains one 90° angle.
the Earth’s atmosphere exerts a pressure of about 14.7 root n: one of the equal factors that, when multiplied
psi at sea level. together, produce a given number or quantity.
power n: 1. for exponents, the number of times a root
number is multiplied by itself. 2. the rate of time of doing secant (sec) n: in a right triangle, the ratio of the hypot-
work, expressed in foot-pounds per unit of time.
enuse to the side adjacent to a given angle, also known as
power factor (pf) n: the ratio of real power to apparent the reciprocal of the cosine function. See cosine.