sensagent's content

• definitions
• synonyms
• antonyms
• encyclopedia

Dictionary and translator for handheld

New : sensagent is now available on your handheld

sensagent's office

Shortkey or widget. Free.

Windows Shortkey: . Free.

Vista Widget : . Free.

Webmaster Solution

Alexandria

A windows (pop-into) of information (full-content of Sensagent) triggered by double-clicking any word on your webpage. Give contextual explanation and translation from your sites !

Try here  or   get the code

SensagentBox

With a SensagentBox, visitors to your site can access reliable information on over 5 million pages provided by Sensagent.com. Choose the design that fits your site.

WordGame

The English word games are:
○   Anagrams
○   Wildcard, crossword
○   Lettris
○   Boggle.

Lettris

Lettris is a curious tetris-clone game where all the bricks have the same square shape but different content. Each square carries a letter. To make squares disappear and save space for other squares you have to assemble English words (left, right, up, down) from the falling squares.

boggle

Boggle gives you 3 minutes to find as many words (3 letters or more) as you can in a grid of 16 letters. You can also try the grid of 16 letters. Letters must be adjacent and longer words score better. See if you can get into the grid Hall of Fame !

English dictionary
Main references

Most English definitions are provided by WordNet .
English thesaurus is mainly derived from The Integral Dictionary (TID).
English Encyclopedia is licensed by Wikipedia (GNU).

The wordgames anagrams, crossword, Lettris and Boggle are provided by Memodata.
The web service Alexandria is granted from Memodata for the Ebay search.
The SensagentBox are offered by sensAgent.

Translation

Change the target language to find translations.
Tips: browse the semantic fields (see From ideas to words) in two languages to learn more.

last searches on the dictionary :

3906 online visitors

computed in 0.078s

 HERTZ HSK165XL.4 6.5" 2-WAY CAR COMPONENT SPEAKER SYSTEM HSK165XL4 (466.66 USD)Commercial use of this term HERTZ ESK 165L.5 6.5" 2-WAY COMPONENT SPEAKER SYSTEM w/ 1" TWEETER ESK165L5 (196.66 USD)Commercial use of this term HERTZ ENERGY ECX-100.4 2-WAY COAXIAL SPEAKERS( PAIR )BRAND NEW IN BOX 80W PEAK (99.0 USD)Commercial use of this term HERTZ HI-ENERGY HCX-165 - SET COAX SPEAKERS 2 WAY 6.5' . BRAND NEW IN BOX (205.0 USD)Commercial use of this term *NEW* HERTZ® ESK 163L 6.5" 3-Way ENERGY Series COMPONENT SPEAKER SYSTEM ESK163L (359.95 USD)Commercial use of this term HERTZ ENERGY EM 100 4 INCH MID RANGE SPEAKERS PAIR - 150 PEAK POWER . BRAND NEW (85.0 USD)Commercial use of this term HERTZ® ESK 165 6.5" 2-WAY ENERGY COMPONENT SPEAKER SYSTEM 200W ESK165 NEW (259.95 USD)Commercial use of this term HERTZ® ESK 163L.5 6 1/2" Energy Series 3-Way Car Audio Component Speaker System (499.95 USD)Commercial use of this term HERTZ® HSK 165XL 6-1/2" 2-Way HI-ENERGY CAR COMPONENT SPEAKER SYSTEM HSK165XL (594.95 USD)Commercial use of this term HERTZ ENERGY EV-165 WOOFER PAIR- 140 PEAK POWER BRAND NEW IN BOX WITH WARRANTY (89.0 USD)Commercial use of this term HERTZ ECX 165.5 6.5" COAXIAL 2-WAY CAR SPEAKERS ECX1655 (146.66 USD)Commercial use of this term HERTZ HCX165.4 6.5" 2-WAY COAXIAL CAR SPEAKERS w/ 3/4" TWEETER HCX1654 (266.66 USD)Commercial use of this term HCX 690 - HERTZ 6x9" 3-WAY HI ENERGY COAXIAL SPEAKERS (369.99 USD)Commercial use of this term HERTZ HSK 165 +2YR WARRANTY 6.5" 500W HI ENERGY COMPONENT CAR SPEAKERS 2WAY 4OHM (422.95 USD)Commercial use of this term HERTZ® DCX 100.3 4" Dieci Series Car Audio / Stereo Coaxial Speakers Pair New (79.95 USD)Commercial use of this term HERTZ® ESK-163L 6.5" 3-WAY ENERGY AUDIO COMPONENT SPEAKER SYSTEM 6-1/2" ESK163L (359.95 USD)Commercial use of this term HERTZ MLK-2TW ML1600.2, ML280.2 & MLCX2-TW 2-WAY COMPONENT SPEAKER SYSTEM MLK2TW (866.66 USD)Commercial use of this term HERTZ ENERGY ESK-130 -2 WAY COMPONENT SPEAKERS 5.25' . BRAND NEW IN BOX (169.0 USD)Commercial use of this term HERTZ ECX 690.5 6" x 9" COAXIAL 2-WAY CAR SPEAKERS ECX6905 (156.66 USD)Commercial use of this term

»

# definitions

## hertz(n.)

1.the unit of frequency; one hertz has a periodic interval of one second

## Hertz(n.)

1.German physicist who with James Franck proved the existence of the stationary energy states postulated by Bohr (1887-1975)

2.German physicist who was the first to produce electromagnetic waves artificially (1857-1894)

# analogical dictionary

divers. (fr)[ClasseParExt.]

physicien. (fr)[ClasseParExt.]

scientifique ou technicien allemand. (fr)[ClasseParExt.]

physicist[Hyper.]

Prix Nobel. (fr)[ClasseParExt.]

physicien allemand. (fr)[ClasseParExt.]

Hertz (n.)

physicien. (fr)[ClasseParExt.]

scientifique ou technicien allemand. (fr)[ClasseParExt.]

physicist[ClasseHyper.]

onde (fr)[termes liés]

physics[Domaine]

Physics[Domaine]

physicien allemand. (fr)[ClasseParExt.]

physics[Domaine]

Human[Domaine]

physicist[Hyper.]

Hertzian[Dérivé]

Hertz (n.)

MESH root[Thème]

hertz [MeSH]

# Hertz

Lights flash at frequency f = 0.5 Hz (Hz = hertz), 1.0 Hz and 2.0 Hz, where $x$ Hz means $x$ flashes per second. T is the period and T = $y$ s (s = second) means that $y$ is the number of seconds per flash. T and f are each other's reciprocal: f = 1/T and T = 1/f.

The hertz (symbol Hz) is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon.[1] One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications. The word "hertz" is named for Heinrich Rudolf Hertz, who was the first to conclusively prove the existence of electromagnetic waves.

## Definition

The hertz is equivalent to cycles per second.[2] In defining the second, the CIPM declared that "the standard to be employed is the transition between the hyperfine levels F = 4, M =  0 and F = 3, M = 0 of the ground state 2S1/2 of the cesium 133 atom, unperturbed by external fields, and that the frequency of this transition is assigned the value 9 192 631 770 hertz"[3] thereby effectively defining the hertz and the second simultaneously.

In English, hertz is used as a plural.[4] As an SI unit, Hz can be prefixed; commonly used multiples are kHz (kilohertz, 103 Hz), MHz (megahertz, 106 Hz), GHz (gigahertz, 109 Hz) and THz (terahertz, 1012 Hz). One hertz simply means "one cycle per second" (typically that which is being counted is a complete cycle); 100 Hz means "one hundred cycles per second", and so on. The unit may be applied to any periodic event—for example, a clock might be said to tick at 1 Hz, or a human heart might be said to beat at 1.2 Hz. The "frequency" (activity) of aperiodic or stochastic events, such as radioactive decay, is expressed in becquerels.

 Hertz Unit system: SI derived unit Unit of... Frequency Symbol: Hz Named after: Heinrich Hertz In SI base units: 1 Hz = 1/s

Even though angular velocity, angular frequency and hertz all have the dimensions of 1/s, angular velocity and angular frequency are not expressed in hertz,[5] but rather in an appropriate angular unit such as radians per second. Thus a disc rotating at 60 revolutions per minute (rpm) is said to be rotating at either 2π rad/s or 1 Hz, where the former measures the angular velocity and the latter reflects the number of complete revolutions per second. The conversion between a frequency f measured in hertz and an angular velocity ω measured in radians per second are:

$\omega = 2\pi f \,$ and $f = \frac{\omega}{2\pi} \,$.

This SI unit is named after Heinrich Hertz. As with every International System of Units (SI) unit whose name is derived from the proper name of a person, the first letter of its symbol is upper case (Hz). When an SI unit is spelled out in English, it should always begin with a lower case letter (hertz), except where any word would be capitalized, such as at the beginning of a sentence or in capitalized material such as a title. Note that "degree Celsius" conforms to this rule because the "d" is lowercase. —Based on The International System of Units, section 5.2.

## History

The hertz is named after the German physicist Heinrich Hertz who made important scientific contributions to the study of electromagnetism. The name was established by the International Electrotechnical Commission (IEC) in 1930.[6] It was adopted by the General Conference on Weights and Measures (CGPM) (Conférence générale des poids et mesures) in 1960, replacing the previous name for the unit, cycles per second (cps), along with its related multiples, primarily kilocycles per second (kc/s) and megacycles per second (Mc/s), and occasionally kilomegacycles per second (kMc/s). The term cycles per second was largely replaced by hertz by the 1970s.

The term "gigahertz", most commonly used in computer processor clock rates and radio frequency (RF) applications, can be pronounced either , with a hard sound, or , with a soft [7] (see giga-#Pronunciation). The prefix "giga-" is derived directly from the Greek "γιγας" ("giant").

## Applications

Sine waves of different frequency.
Details of a heartbeat as an example of a non-sinusoidal periodic phenomenon that can be described in terms of hertz. Two complete cycles are illustrated.

### Vibration

Sound is a traveling wave which is an oscillation of pressure. Humans perceive frequency of sound waves as pitch. Each musical note corresponds to a particular frequency which can be measured in hertz. An infant's ear is able to perceive frequencies ranging from 20 Hz to 20,000 Hz; the average adult human can hear sounds between 20 Hz and 16,000 Hz.[8] The range of ultrasound, high-intensity infrasound and other physical vibrations such as molecular vibrations extends into the megahertz range and well beyond.

Electromagnetic radiation is often described by its frequency—the number of oscillations of the perpendicular electric and magnetic fields per second—expressed in hertz.

Radio frequency radiation is usually measured in kilohertz (kHz), megahertz (MHz), or gigahertz (GHz). Light is electromagnetic radiation that is even higher in frequency, and has frequencies in the range of tens (infrared) to thousands (ultraviolet) of terahertz. Electromagnetic radiation with frequencies in the low terahertz range, (intermediate between those of the highest normally usable radio frequencies and long-wave infrared light), is often called terahertz radiation. Even higher frequencies exist, such as that of gamma rays, which can be measured in exahertz. (For historical reasons, the frequencies of light and higher frequency electromagnetic radiation are more commonly specified in terms of their wavelengths or photon energies: for a more detailed treatment of this and the above frequency ranges, see electromagnetic spectrum.)

### Computing

In computing, most central processing units (CPU) are labeled in terms of their clock rate expressed in megahertz or gigahertz (106 or 109 hertz, respectively). This number refers to the frequency of the CPU's master clock signal ("clock rate"). This signal is simply an electrical voltage which changes from low to high and back again at regular intervals. This signal is a square wave. Hertz has become the primary unit of measurement accepted by the general populace to determine the performance of a CPU, but many experts have criticized this approach, which they claim is an easily manipulable benchmark.[9] For home-based personal computers, the CPU has ranged from approximately 1 megahertz in the late 1970s (Atari, Commodore, Apple computers) to up to 6 GHz in the present (IBM POWER processors) and up to 8 GHz overclocked (AMD FX processors).[10]

Various computer buses, such as the front-side bus connecting the CPU and northbridge, also operate at different frequencies in the megahertz range

## SI multiples

Submultiples Multiples Value Symbol Name Value 10−1 Hz dHz decihertz 101 Hz daHz decahertz 10−2 Hz cHz centihertz 102 Hz hHz hectohertz 10−3 Hz mHz millihertz 103 Hz kHz kilohertz 10−6 Hz µHz microhertz 106 Hz MHz megahertz 10−9 Hz nHz nanohertz 109 Hz GHz gigahertz 10−12 Hz pHz picohertz 1012 Hz THz terahertz 10−15 Hz fHz femtohertz 1015 Hz PHz petahertz 10−18 Hz aHz attohertz 1018 Hz EHz exahertz 10−21 Hz zHz zeptohertz 1021 Hz ZHz zettahertz 10−24 Hz yHz yoctohertz 1024 Hz YHz yottahertz Common prefixed units are in bold face.

### Frequencies not expressed in hertz

Even higher frequencies are believed to occur naturally, in the frequencies of the quantum-mechanical wave functions of high-energy (or, equivalently, massive) particles, although these are not directly observable, and must be inferred from their interactions with other phenomena. For practical reasons, these are typically not expressed in hertz, but in terms of the equivalent quantum energy, which is proportional to the frequency by the factor of Planck's constant.

## References

1. ^ "hertz". (1992). American Heritage Dictionary of the English Language, 3rd ed. Boston: Houghton Mifflin.
2. ^
3. ^ "[Resolutions of the CIPM, 1964 - Atomic and molecular frequency standards"]. SI brochure, Appendix 1. Retrieved 2010-20-26.
4. ^ NIST Guide to SI Units - 9 Rules and Style Conventions for Spelling Unit Names, National Institute of Standards and Technology
5. ^
6. ^ "IEC History". Iec.ch. 1904-09-15. Retrieved 2012-04-28.
7. ^ "Gigahertz" in Dictionary.com Unabridged. Dictionary.
8. ^ Ernst Terhardt (2000-02-20). "Dominant spectral region". Mmk.e-technik.tu-muenchen.de. Retrieved 2012-04-28.
9. ^ Amit Asaravala (2004-03-30). "Good Riddance, Gigahertz". Wired.com. Retrieved 2012-04-28.
10. ^ By RMorin on Sep 23, 2011. "AMD Breaks 8GHz Overclock with Upcoming FX Processor, Sets World Record". HotHardware. Retrieved 2012-04-28.