Radiologic Physics: Simplified Math & Units of Measurement

Flashcards covering key vocabulary related to radiologic physics, simplified math, and units of measurement, including number types, mathematical operations, fractions, percents, scientific notation, and measurement systems.

Exponent

The exponent of a number defines how many times to multiply the number repeatedly by itself (base), also called 'power or index'.

Base (Exponent)

The number being multiplied repeatedly when using an exponent.

Digits

In the Arabic system, the 10 symbols used: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.

Numeral

A group of digits that makes a number, where a value is placed for each digit.

Natural numbers

Counting numbers without zero (example: 1, 2, 3, 4, 5, 6, 7, 8, 9).

Whole numbers

All counting numbers with zero (example: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9).

Even numbers

Any number divisible by 2 with no remainder.

Odd number

Any number divisible by 2 with a remainder.

Prime numbers

A number which is greater than 1 and has exactly 2 factors.

Composite numbers

Numbers which are greater than 1 and not prime.

Integers

A set of all natural counting numbers including zero, negative and positive numbers (example: …, -3, -2, -1, 0, 1, 2, 3…).

Positive integers

A set of positive counting numbers (example: 1, 2, 3, 4, 5…).

Negative integers

A set of negative counting numbers (example: -1, -2, -3, -4, -5…).

Equation

A statement that sets two mathematical expressions equal to each other (example: a + b = c + d).

Variables (or terms)

The unknown quantities represented by letters in an equation.

Fractions

Defined as one or more equal parts of a number.

Numerator

The number above the line in a fraction, representing the number of parts.

Denominator

The number below the line in a fraction, representing the total number of parts.

Improper fraction

A fraction where the numerator is bigger than the denominator (example: 5/4).

Proper fraction

A fraction where the numerator is smaller than the denominator (example: 4/5).

Least Common Denominator (LCD)

The smallest number which is divisible by all denominators, used when adding or subtracting fractions with different denominators.

Dividend

The first fraction that is to be divided in a division operation.

Divisor

The fraction that does the dividing in a division operation.

Percent

A special type of fraction, indicated by the symbol '%', meaning 'per hundred'.

Decimal

A method to show a number as a multiple of 10.

Ratio

A relationship between two numbers or quantities, indicating how many times the first number is larger or smaller than the second.

Proportion

An equation that states that two ratios are equal.

Direct proportion

If one number increases then the second number also increases by the same factor.

Inverse proportion

If one number increases then the second number decreases by the same factor.

Negative exponent

An exponent equivalent to the inverse of the same number with a positive exponent, representing a very small number.

Scientific Notation

A way that scientists easily handle very large numbers or very small numbers.

Leading Zeros

Zeros before a non-zero digit; they are never significant in scientific notation.

Squeeze Zeros

Zeros which are in-between non-zero digits; they are always significant in scientific notation.

Trailing Zeros

Zeros after a non-zero digit; they are significant if and only if the number is represented with a decimal point in scientific notation.

Coefficient (Scientific Notation)

The decimal part in scientific notation; it must be greater than or equal to 1 and less than 10.

Base (Scientific Notation)

Always 10 for scientific notation.

Exponent (Scientific Notation)

The power for the base 10 in scientific notation.

Measurement

Consists of two parts: Magnitude (quantity or amount) and Unit.

Unit

An agreed, understood, and adopted society-wide measure by which other quantities of the same kind are measured.

Standard unit

The basic units in any particular system of measurement.

English or British System

A system of measurement mainly used in England.

Metric system (MKS system)

A universal system used mainly in science where all units are related by a factor of 10.

SI (Standard International System)

An extended Metric (MKS) system of measurement, commonly used in Radiography.

Base quantity/unit (Metric/SI)

A fundamental unit that corresponds to a certain kind of measurement (e.g., meter for length, kilogram for mass, second for time).

Prefix (Metric/SI)

A component that combines with a base unit to make a complete system (e.g., centi-, kilo-, milli-).

Fundamental Quantities

Basic, independent quantities of measurement such as length, mass, and time.

Length (l)

A fundamental quantity with the SI unit of meter (m).

Mass (m)

A fundamental quantity with the SI unit of kilogram (kg).

Time (t)

A fundamental quantity with the SI unit of second (s).

Electrical current (I)

A fundamental quantity with the SI unit of Ampere (A).

Temperature (T)

A fundamental quantity with the SI unit of Kelvin (K).

Amount of substance (n)

A fundamental quantity with the SI unit of mole (mol).

Luminous intensity (Iv)

A fundamental quantity with the SI unit of candela (cd).

Derived Quantities

Combinations of one or more base quantities, often complex and having special names.

Area

A derived quantity calculated as length x width, with the unit m^2 (square meter).

Volume

A derived quantity calculated as length x width x height, with the unit m^3 (cubic meter).

Velocity

A derived quantity representing distance traveled per unit time, with the unit m/s.

Acceleration

A derived quantity with the unit m/s^2.

Force

A derived quantity with the unit kg-m/s^2.

Work and energy

Derived quantities with the unit kg-m^2/s^2.

Power

A derived quantity with the unit kg-m^2/s^3.

Density (mass/volume)

A derived quantity representing mass per volume, with the unit kg/m^3.

Exposure (Radiography)

A special quantity in radiography measured in Roentgen or KERMA.

Absorbed Dose (Radiography)

A special quantity in radiography measured in rad or Gray.

Dose Equivalent (Radiography)

A special quantity in radiography measured in rem or Sievert.

Radioactivity (Radiography)

A special quantity in radiography measured in Curie or Becquerel.