Copy of `Talk Talk - Communication terms`

The wordlist doesn't exist anymore, or, the website doesn't exist anymore. On this page you can find a copy of the original information. The information may have been taken offline because it is outdated.


 Talk Talk - Communication terms
Category: General technical and industrial
Date & country: 28/05/2010, UK
Words: 18630


pika
Any small mammal of the family Ochotonidae, belonging to the order Lagomorpha (rabbits and hares). The single genus Ochotona contains about 15 species, most of which live in mountainous regions of Asia, although two species are native to North America. Pikas have short, rounded ears, and most species are about 20 cm/8 in long...

pistil
General term for the female part of a flower, either referring to one single carpel or a group of several fused carpels

pinnate leaf
Leaf that is divided up into many small leaflets, arranged in rows along either side of a midrib, as in ash trees (Fraxinus). It is a type of compound leaf. Each leaflet is known as a pinna, and where the pinnae are themselves divided, the secondary divisions are known as pinnules

pitot tube
Instrument that measures fluid (gas or liquid) flow. It is used to measure the speed of aircraft, and works by sensing pressure differences in different directions in the airstream. It was invented in the 1730s by the French scientist Henri Pitot (1695–1771)

piston
(technology) Any disc or cylinder, circular in cross-section, used in reciprocating engines (steam, petrol, diesel oil) to harness power. Pistons are driven up and down in cylinders by expanding steam or hot gases. They pass on their motion via a connecting rod and crank to a crankshaft, w...

Pink Floyd
British psychedelic rock group, formed in 1965. The original members were Syd Barrett (1946–2006), Roger Waters (1944– ), Richard Wright (1945– ), and Nick Mason (1945– ). Dave Gilmour (1944– ) joined the band in 1968. Their albums include The Dark Side of the Moon (1973) and ...

pidgin language
Any of various trade jargons, contact languages, or lingua francas arising in ports and markets where people of different linguistic backgrounds meet for commercial and other purposes. Usually a pidgin language is a rough blend of the vocabulary of one (often dominant) language with the syntax or grammar of one or more other (often dependent) group...

pidgin English
Originally a trade jargon developed between the British and the Chinese in the 19th century, but now commonly and loosely used to mean any kind of `broken` or `native` version of the English language. Pidgin is believed to have been a Chinese pronunciation of the English word business. There...

pilgrimage
Click images to enlargeJourney to sacred places inspired by religious devotion. For Hindus, the holy places include Varanasi and the purifying River Ganges; for Buddhists, the places connected with the crises of Buddha's career; for the ancient Greeks, shrines such as those at Delphi and Ephesus; for Jews,...

Pilgrimage of Grace
Rebellion against Henry VIII of England 1536–37, originating in Yorkshire and Lincolnshire. The uprising was directed against the policies of the monarch (such as the Dissolution of the Monasteries during the Reformation and the effects of the enclosure of common land)

Piccard, Auguste Antoine
Swiss scientist. In 1931–32 he and his twin brother, Jean Félix (1884–1963), made ascents to 17,000 m/55,000 ft in a balloon of his own design, resulting in useful discoveries concerning stratospheric phenomena such as cosmic radiation. He also built and used, with his son Jacques Ernest (1922– ), bathyscaphs for resear...

piezoelectric effect
Property of some crystals (for example, quartz) to develop an electromotive force or voltage across opposite faces when subjected to tension or compression, and, conversely, to expand or contract in size when subjected to an electromotive force. Piezoelectric crystal oscillators are used as frequency standards (for example, replacing balance wheels...

pitch
(music) In music, the technical term used to describe how high or low a note is. It depends on the frequency (number of vibrations per second) of the sound, which is measured in hertz (Hz). Pitch also refers to the standard to which instruments are tuned. Nowadays the internationally agreed...

pistol
Any small firearm designed to be fired with one hand. Pistols were in use from the early 15th century. The problem of firing more than once without reloading was tackled by using many combinations of multiple barrels, both stationary and revolving. A breech-loading, multichambered revolver from 1650 still survives; the first practical solut...

piano
(instrument) Keyboard instrument. The sound is produced when a depressed key strikes the strings with a felt-covered hammer, causing them to vibrate. It is therefore a form of mechanized dulcimer, a percussion instrument. It is different from the earlier harpsichord, a mechanized harp, whe...

Piranesi, Giambattista
(Giovanni Battista) Italian architect and graphic artist. He made powerful etchings of Roman antiquities and was an influential theorist of architecture, advocating imaginative use of Roman models. His series of etchings Carceri d'Invenzione/Prisons of Invention (<...

Pinochet
(Ugarte) Chilean soldier and military dictator 1973–90. He came to power when a coup backed by the US Central Intelligence Agency (CIA) ousted and killed President Salvador Allende. He governed ruthlessly and crushed all political opposition, including more than 3,000 people who `van...

pizzicato
In music, an instruction to string players to pluck the strings with the fingers instead of using the bow. It is frequently abbreviated to `pizz`. Good examples of pizzicato are in the Pizzicato Polka (1870) by Johann Strauss II and Josef Strauss, and in the `Playful Pizzicato` of Benjamin Britten's
Pius IV
Pope from 1559, of the Medici family. He reassembled the Council of Trent (see Counter-Reformation under Reformation) and completed its work in 1563

Pius V, Antonio Etrislieri
Pope from 1566. His early career was in the Inquisition, a role which brought him the support of Paul IV who made him a cardinal in 1558. From the beginning of his own pontificate, he stressed his determination to carry out the reforms of the Council of Trent. He also excommunicated Elizabeth I of England, and organized the expedition against the T...

Pius VI
Pope from 1775. He strongly opposed the French Revolution, and died a prisoner in French hands

Pius VII
Pope from 1800. He concluded a concordat (papal agreement) with France in 1801 and took part in Napoleon's coronation, but relations became strained. Napoleon annexed the papal states, and Pius was imprisoned 1809–14. After his return to Rome in 1814, he revived the Jesuit order

Pius IX
Pope from 1846. He never accepted the incorporation of the papal states and of Rome in the kingdom of Italy. He proclaimed the dogmas of the Immaculate Conception of the Virgin in 1854 and papal infallibility in 1870; his pontificate was the longest in history

Pius XII
Pope from 1939. He was conservative in doctrine and politics, and condemned modernism. In 1950 he proclaimed the dogma of the bodily assumption of the Virgin Mary, and in 1951 restated the doctrine (strongly criticized by many) that the life of an infant must not be sacrificed to save a mother in labour. He was criticized for failing to speak out a...

Piggott, Lester Keith
English jockey. He adopted a unique high riding style and was renowned as a brilliant tactician. A champion jockey 11 times between 1960 and 1982, he rode a record nine Derby winners. Piggott retired from riding in 1985 and took up training. In 1987 he was imprisoned for tax evasion. He returned to racing in 1990 and rode over 5,300 winners in 28 c...

pietra dura
Italian technique of inlaying furniture with semi-precious stones, such as agate or quartz, in a variety of colours, to create pictures or patterns

Piura
Capital of Piura department, in the arid coastal region of northwest Peru, situated on the Piura River 160 km/100 mi southwest of Punta Pariñas; population (2005) 461,800. It is an agricultural centre for the surrounding region (made viable with irrigation systems) which produces rice, cotton, and corn. The first colonial settlement in...

Piscis Austrinus
Constellation of the southern hemisphere near Capricornus. Its brightest star is the first-magnitude Fomalhaut

Pill, the
Commonly used term for the contraceptive pill, based on female hormones. The combined pill, which contains synthetic hormones similar to oestrogen and progesterone, stops the production of eggs, and makes the mucus produced by the cervix hostile to sperm. It is the most effective form of contraception apart from sterilization, being more than 99...

pipette
Device for the accurate measurement of a known volume of liquid, usually for transfer from one container to another, used in chemistry and biology laboratories. A pipette may be a slender glass tube, often with an enlarged bulb, which is calibrated in one or more positions; or it may be a plastic device with an adjustable plunger, fitted with o...

Pickford, Mary
Canadian-born US actor. The first star of the silent screen, she was known as `America's Sweetheart,` and played innocent ingenue roles into her thirties. She and her second husband (from 1920), Douglas Fairbanks Sr, were known as `the world's sweethearts`. With her husband, Charlie Chaplin, and D W Griffith she foun...

pion
In physics, a subatomic particle with a neutral form (mass 135 MeV) and a charged form (mass 139 MeV). The charged pion decays into muons and neutrinos and the neutral form decays into gamma-ray photons. They belong to the hadron class of elementary particles, and consist of pairs of quarks. The mass of a charged pion is 273 times that of an el...

pigeon hawk
Another name for the merlin, a small falcon

Pittsburgh
Second-largest city in Pennsylvania, USA, in Allegheny County at the confluence of the Allegheny and Monongahela rivers, forming the Ohio River; population (2000 est) 334,600. It is a business and financial centre with one of the largest river ports in the world (it is the 11th-largest port in the USA overall and the largest inland port...

pitch
(mechanics) In mechanics, the distance between the adjacent threads of a screw or bolt. When a screw is turned through one full turn it moves a distance equal to the pitch of its thread. A screw thread is a simple type of machine, acting like a rolled-up inclined plane, or ramp (as may be ...

pit bull terrier
Variety of dog that was developed in the USA solely as a fighting dog. It usually measures about 50 cm/20 in at the shoulder and weighs roughly 23 kg/50 lb, but there are no established criteria since it is not recognized as a breed by either the American or British Kennel Clubs. Selective breeding for physical strength and aggression has c...

PIN
In banking, a unique number used as a password to establish the identity of a customer using an automatic cash dispenser. The PIN is normally encoded into the magnetic strip of the customer's bank card and is known only to the customer and to the bank's computer. Before a cash dispenser will issue money or information, the customer must ins...

pie chart
Method of displaying proportional information by dividing a circle up into different-sized sectors (slices of pie). The angle of each sector is proportional to the size, expressed as a percentage, of the group of data that it represents. For example, data from a traffic survey could be presented in a pie chart in the following way: (1) conv...

pi
Ratio of the circumference of a circle to its diameter. Pi is an irrational number: it cannot be expressed as the ratio of two integers, and its expression as a decimal never terminates and never starts recurring. The value of pi is 3.1415926, correct to seven decimal places. Common approximations to pi are 22/7 and 3.14, although the value...

pictogram
Pictorial way of presenting statistical data, in which a symbol is used to represent a specific quantity of items. For example, the table shows how many cans of lemonade were sold in one week from a vending machine: This data can be represented in a pictogram:

Pinatubo, Mount
Active volcano on Luzon Island, the Philippines, 88 km/55 mi north of Manila. Dormant for 600 years, it erupted in June 1991, killing 343 people and leaving as many as 200,000 homeless. Surrounding rice fields were covered with 3 m/10 ft of volcanic ash

piano score
In music, a reduction of an orchestral or vocal score to two staves of music to be played on the piano

PIPEX
In computing, UK-based Internet provider that started operations in 1992, specializing in serving the commercial sector. The company became one of the UK's major backbone providers; it was acquired by UUNET in 1996 and then by Tiscali in 2007

pinnacle
In Gothic architecture, a pyramidal or conical feature, often richly ornamented with crockets (small carved ornaments). It commonly crowns a buttress, and serves a structural purpose because its weight helps to counteract the outward thrust of a vault or roof-truss

piano trio
In music, a group of three players made up of piano, violin, and cello. The term also refers to the music written for such a group. Composers who wrote piano trios include Joseph Haydn, Wolfgang Amadeus Mozart, Ludwig van Beethoven (the `Ghost` trio and the `Archduke` trio), Johannes Brahms, Franz Schubert, Antonín Dvor...

pilgrimage, medieval
In the Middle Ages, the great centres of Christian pilgrimage were Jerusalem, Rome, the tomb of St James of Compostela in Spain, and the shrine of St Thomas à Becket in Canterbury, England. Pilgrimages had been common since the 2nd century and, as a result of the growing frequency and numbers of pilgrimages, the monasteries established numerou...

PIF
Abbreviation for Pacific Islands Forum

pinching
In ceramics, a simple method used to make basic container shapes, or pinch pots, from a ball of clay. The clay is drawn out with the fingers by literally `pinching` the clay between the thumb and forefingers to form the sides of the pinch pot

picturesque
In art, having those qualities that characterize a good picture, natural or artificial. In particular it refers to something pretty or attractive, especially in a quaint or charming way

pigment
In art and crafts, a colouring-matter used in paint or dye. In the past, pigments were powders made by grinding various minerals, plants, and even animal or insect parts. The most expensive pigments were gold, vermilion (a red pigment made from sulphur and mercury), and ultramarine (a blue pigment made from the gemstone lapis lazuli). Modern pi...

Piemonte
Italian name for Piedmont, a region of northern Italy

Picardie
French name for Picardy, a region of northern France

pivot
In physics, the part of a mechanism or machine that allows a turning motion. For example, in a see-saw the pivot at the centre allows one side to move down when an effort is applied and the opposite side with a load to move up. The pivot in a pair of scissors is the screw that holds the two parts of the scissors together

pilgrim festivals
In Judaism, the festivals of Pesach (Passover), Shavuot (Pentecost), and Succoth, which together commemorate the Exodus from Egypt and the journey through the desert to Canaan, the Promised Land. The term derives from the pilgrimages made to the Temple of Jerusalem to offer sacrifices for the celebrations, until the Temple's destruction in AD 7...

PIC device
Microcontroller that can be programmed to carry out specific tasks. The PIC contains a low-power microprocessor, together with a small amount of Flash RAM used to store the program and a smaller amount of working RAM in which the program data is held while running. PICs also contain all the necessary circuitry to connect to the outside world, p...

PKK
Abbreviation for Workers' Party of Kurdistan, a Kurdish guerrilla organization

plane
In botany, any of several trees belonging to the plane family. Species include the oriental plane (P. orientalis), a favourite plantation tree of the Greeks and Romans, and the American plane or buttonwood (P. occidentalis). A hybrid of these two is the London pl...

plantain
Any of a group of northern temperate plants. The great plantain (P. major) is low-growing with large oval leaves close to the ground, grooved stalks, and spikes of green flowers with purple anthers (in which the pollen matures) followed by seeds, which are used in bird food. (Genus Plantago, family Plantagi...

plankton
Small, often microscopic, forms of plant and animal life that live in the upper layers of fresh and salt water, and are an important source of food for larger animals. Marine plankton is concentrated in areas where rising currents bring mineral salts to the surface

Plymouth Brethren
Fundamentalist Christian Protestant sect characterized by extreme simplicity of belief, founded in Dublin in about 1827 by the Reverend John Nelson Darby (1800–1882). The Plymouth Brethren have no ordained priesthood, affirming the ministry of all believers, and maintain no church buildings. They hold prayer meetings and Bible study in members...

Plymouth
(UK city) Seaport and administrative centre of Plymouth City unitary authority in southwest England, at the mouth of the river Plym, 179 km/112 mi southwest of Bristol; population (2001) 240,700. The city's focus is based around its three harbours, and industries include marine and...

Plutarch
Greek biographer and essayist. He is best remembered for his Lives, a collection of short biographies of famous figures from Greek and Roman history arranged in contrasting pairs (for example, Alexander the Great and Julius Caesar are paired). He also wrote Moralia, a collection of essays on moral and social th...

Plovdiv
Industrial city (textiles, chemicals, leather, tobacco) in Bulgaria, on the River Maritsa; population (2001) 340,600. Conquered by Philip of Macedon in the 4th century BC, it was known as Philippopolis (`Philip's city`). It was the capital of Roman Thrace

Plisetskaya, Maya Mikhailovna
Russian ballerina and actor. She attended the Moscow Bolshoi Ballet School and became prima ballerina of the Bolshoi Ballet In 1945. An extremely strong yet supple dancer of great exuberance, she is noted for her fast spins, scissor-like jumps, and head-to-heel backward kicks, which she displayed to best advantage in the role of Kitri i...

Pliny the Younger
Roman administrator. He was the nephew of Pliny the Elder. His correspondence is of great interest; among his surviving letters are those describing the eruption of Vesuvius, his uncle's death, and his correspondence with the emperor Trajan

Pliny the Elder
Roman scientific encyclopedist and historian. Many of his works have been lost, but in Historia naturalis/Natural History, probably completed AD 77, Pliny surveys all the known sciences of his day, notably astronomy, meteorology, geography, mineralogy, zoology, and botany. Pliny states that he has covered 20,000 subjects of i...

pleurisy
Inflammation of the pleura, the thin, secretory membrane that covers the lungs and lines the space in which they rest. Pleurisy is nearly always due to bacterial or viral infection, but may also be a complication of other diseases. Normally the two lung surfaces move easily on one another, lubricated by small quantities of fluid. When the pleura is...

plebeian
Roman citizen who did not belong to the privileged class of the patricians. During the 5th–4th centuries BC, plebeians waged a long struggle to win political and social equality with the patricians, eventually securing admission to the offices formerly reserved for patricians

plebiscite
Referendum or direct vote by all the electors of a country or district on a specific question. Since the 18th century plebiscites have been employed on many occasions to decide to what country a particular area should belong; for example, in Upper Silesia and elsewhere after World War I, and in the Saar in 1935. The term fell into disuse during...

Plataea, Battle of
Battle in 479 BC, in which the Greeks defeated the Persians during the Persian Wars

Plautus, Titus Maccius
Roman comic dramatist. Born in Umbria, he settled in Rome and began writing plays about 224 BC. Twenty-one comedies survive in his name; 35 other titles are known. Many of his plays are based on Greek originals by playwrights such as Menander, to which Plautus added his own brand of native wit and sharp character-drawing. He had a perfe...

plastic surgery
Surgical speciality concerned with the repair of congenital defects and the reconstruction of tissues damaged by disease or injury, including burns. If a procedure is undertaken solely for reasons of appearance, for example, the removal of bags under the eyes or a double chin, it is called cosmetic surgery

plaster of Paris
Form of calcium sulphate CaCo3.1/2H2O, obtained from gypsum; it is mixed with water for making casts and moulds

plasmapheresis
Technique for acquiring plasma from blood. Blood is withdrawn from the patient and separated into its components (plasma and blood cells) by centrifugal force in a continuous-flow cell separator. Once separated, the plasma is available for specific treatments. The blood cells are transfused back into the patient

plasma
(physics) In physics, ionized gas produced at extremely high temperatures, as in the Sun and other stars. It contains positive and negative charges in equal numbers. It is a good electrical conductor. In thermonuclear reactions the plasma produced is confined through the use of magnetic fields

Plantagenet
English royal house, which reigned from 1154 to1399, and whose name comes from the nickname of Geoffrey, Count of Anjou (1113–1151), father of Henry II, who often wore in his hat a sprig of broom, planta genista. In the 1450s, Richard, Duke of York, took `Plantagenet` as a surname to emphasize his superior claim to...

Plains Indian
Member of any of the American Indian peoples of the Great Plains, a region of North America extending over 3,000 km/2,000 mi from Alberta, Canada, to Texas, USA. The Plains Indians were drawn from diverse linguistic stocks fringing the Plains. They shared many cultural traits, especially the nomadic hunting of the North American buffalo (bison)...

plague
Term applied to any epidemic disease with a high mortality rate, but it usually refers to bubonic plague. This is a disease transmitted by fleas (carried by the black rat), which infect the sufferer with the bacillus Yersinia pestis. An early symptom is swelling of lymph nodes, usu...

Pluto
(astronomy) Dwarf planet. Until its reclassification in 2006 it was considered to be the smallest and, usually, outermost planet of the Solar System. The existence of Pluto was predicted by calculation by US astronomer Percival Lowell and located by US astronomer Clyde Tombaugh in 1930. Its hi...

Pleiades
(astronomy) In astronomy, an open star cluster about 400 light years away from Earth in the constellation Taurus, represented as the Seven Sisters of Greek mythology. Its brightest stars (highly luminous, blue-white giants only a few million years old) are visible to the naked eye, but the...

Plough, the
Popular name for the most prominent part of the constellation Ursa Major

planetary nebula
Shell of gas thrown off by a star at the end of its life. Planetary nebulae have nothing to do with planets. They were named by German-born English astronomer William Herschel, who thought their rounded shape resembled the disc of a planet. After a star such as the Sun has expanded to become a red giant, its outer layers are ejected into space ...

platinum
Heavy, soft, silver-white, malleable and ductile, metallic element, atomic number 78, relative atomic mass 195.09. It is the first of a group of six metallic elements (platinum, osmium, iridium, rhodium, ruthenium, and palladium) that possess similar properties, such as resistance to tarnish, corrosion, and attack by acid, and that often occur ...

plastic
(chemistry) Click images to enlargeAny of the stable synthetic materials that are fluid at some stage in their manufacture, when they can be shaped, and that later set to rigid or semi-rigid solids. Plastics today are chiefly derived from petrole...

plover
Any shore bird of the family Charadriidae, order Charadriiformes, found worldwide. Plovers are usually black or brown above and white below, and have short bills. The European golden plover Pluviatilis apricaria, of heathland and sea coast, is about 28 cm/11 in long. In winter the upper parts are a sooty black with large yell...

platypus
Monotreme, or egg-laying, mammal Ornithorhynchus anatinus, found in Tasmania and eastern Australia. Semiaquatic, it has small eyes and no external ears, and jaws resembling a duck's beak. It lives in long burrows along river banks, where it lays two eggs in a rough nest. It...

plaice
Fish Pleuronectes platessa belonging to the flatfish group, abundant in the North Atlantic. It is white beneath and brownish with orange spots on the `eyed` side. It can grow to 75 cm/2.5 ft long and weigh about 2 kg/4.5 lb

plant classification
Taxonomy or classification of plants. Originally the plant kingdom included bacteria, diatoms, dinoflagellates, fungi, and slime moulds, but these are not now thought of as plants. The groups that are always classified as plants are the bryophytes (mosses and liverworts), pteridophytes (ferns, horsetails, and club mosses), gymnosperms (conifers, ye...

plant
Click images to enlargeOrganism that carries out photosynthesis, has cellulose cell walls and complex cells, and is immobile. A few parasitic plants have lost the ability to photosynthesize but are still considered to be plants. Plants are autotrophs, that is, they make carbohydrates from water and carbon dioxide, and are...

plate tectonics
Click images to enlargeTheory formulated in the 1960s to explain the phenomena of continental drift and sea-floor spreading, and the formation of the major physical features of the Earth's surface. The Earth's outermost layer, the lithosphere, is seen as a jigsaw puzzle of rigid major and minor plates that mov...

plumule
Part of a seed embryo that develops into the shoot, bearing the first true leaves of a plant. In most seeds, for example the sunflower, the plumule is a small conical structure without any leaf structure. Growth of the plumule does not occur until the cotyledons have grown above ground. This is epigeal germination. However, in seeds such as the bro...

plastid
General name for a cell organelle of plants that is enclosed by a double membrane and contains a series of internal membranes and vesicles. Plastids contain DNA and are produced by division of existing plastids. They can be classified into two main groups: the chromoplasts, which contain pigments such as carotenes and chlorophyll, and the leuco...

plasma
(biology) In biology, the liquid component of the blood. It is a straw-coloured fluid, largely composed of water (around 90%), in which a number of substances are dissolved. These include a variety of proteins (around 7%) such as fibrinogen (important in blood clotting), inorganic ...

plywood
Manufactured panel of wood widely used in building. It consists of several thin sheets, or plies, of wood, glued together with the grain (direction of the wood fibres) of one sheet at right angles to the grain of the adjacent plies. This construction gives plywood equal strength in every direction

placenta
Click images to enlargeOrgan that attaches the developing embryo or fetus to the uterus (womb) in placental mammals (mammals other than marsupials, platypuses, and echidnas). Composed of maternal and embryonic tissue, it links the blood supply of the embryo to the blood supply of the mother, allowing the exchange of oxyge...

Plimsoll line
Loading mark painted on the hull of merchant ships, first suggested by the 19th-century English politician Samuel Plimsoll. It shows the depth to which a vessel may be safely (and legally) loaded

plotter
Device that draws pictures or diagrams under computer control. Plotters are often used for producing business charts, architectural plans, and engineering drawings. Flatbed plotters move a pen up and down across a flat drawing surface, whereas roller plotters roll the drawing paper past the pen as it...

planet
Celestial body in our Solar System that is in orbit around the Sun, is large enough to be spherical, and which dominates its orbit (sweeping its neighbourhood clear). There are eight planets in the Solar System orbiting the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Neptune and Uranus. Th...

pluralism
(politics) In political science, the view that decision-making in current liberal democracies is the outcome of competition among several interest groups in a political system characterized by free elections, representative institutions, and open access to the organs of power. This concept...

Planck, Max Karl Ernst Ludwig
German physicist who was awarded the Nobel Prize for Physics in 1918 for his formulation of the quantum theory in 1900. His research into the manner in which heated bodies radiate energy led him to report that energy is emitted only in indivisible amounts, called `quanta`, the magnitudes of which are proportional to the frequency of the r...