67 %
33 %
Information about ptr

Published on January 31, 2009

Author: sheikmohamed


Points to Remember : ? The measuring process is basically a comparison process. We select the unit of measurement (u) and find number of times (n) this unit is contained in the quantity (q). Then q = nu. ? The units of length (metre), mass (kilogram), time (sec), temp. (ºK), electric current (ampere), luminous intensity (candela) and quantity of matter (mole) are treated as fundamental units. The units of plane angle (radian) and solid angle (steradian) are supplementary units. The units of all other quantities, which can be obtained from the fundamental and supplementary units are called Derived units. For example, derived units of force, work/energy, power, electric potential and electric capacity are Newton (n), joule (J), watt (W), coulomb (C), volt (V) and farad (F) respectively. Points to Remember Slide 3: ? Some important Practical units are: (i) Astronomical unit, 1AU = 1.496 × 1011m (ii) Light year, 1ly = 9.46 × 1015m (iii) parsec, 1 par sec = 3.084 × 1016m (iv) Angstrom, 1Å = 10-10m (v) Fermi, 1F = 10-15m (vi) 1 barn = 10-28m2 (vii) 1 shake = 10-8s (viii) 1bar = 760 torr. Slide 4: ? The order of magnitude of a quantity gives us a value nearest to the actual value of the quantity in suitable powers of 10. For this, a number less than 5 is treated as 1 and a number between 5 and 10 is treated as 10. ? The masses we come across vary form 10-30 kg (mass of electron) to 1055 kg (mass of universe). An inertial balance is used for measuring inertial mass of a body and a common balance is used for measuring weight of a body. ? A quantity like angle has no dimensions, but it has units. The reverse is not true. ? The dimensional formulae of non mechanical quantities can be obtained using all the seven fundamental units and two supplementary units on SI. Slide 5: ? Three uses of dimensional analysis are: Conversion of one system of units into another. Checking the accuracy of various formulae. Derivation of formulae. In the last two advantages, we use the principle of homogeneity of dimensions. According to this principle, a formula is correct when dimensions of mass, length and time on one side of the formula are equal to their respective dimensions on other side of the formula. ? Note that only like quantities can be added on subtracted from one another. ? A coherent system is based on a certain set of fundamental units, from which derived units are obtained by multiplication or division without introducing numerical factors. ? Shortest time interval measured indirectly so far 10-22sec.

Add a comment

Related presentations

Related pages

Home - PTR Messtechnik GmbH

PTR Messtechnik – Qualität aus Tradition. Wer auf Dauer Spitzenleistung bringt, darf nichts dem Zufall überlassen. Bereits seit 1979 bürgt der Name ...
Read more

PTR Resource Record – Wikipedia

PTR (kurz für ‚Pointer‘) Resource Records ordnen im Domain Name System einer gegebenen IP-Adresse einen oder mehrere Hostname(s) zu. Sie stellen damit ...
Read more

Produkte - PTR Messtechnik GmbH

Crossreferenz Um für ein Produkt eines Wettbewerbers den optimalen PTR-Ersatz zu finden, verwenden Sie bitte unsere Crossreferenz ...
Read more


Von der Automobilbranche bis hin zur Luft- und Raumfahrt – innerhalb der GLOBAL Beam Technologies Group beliefern wir unsere namhaften Kunden auf aller Welt.
Read more

PTR - What does PTR stand for? The Free Dictionary

Acronym Definition; PTR: Pointer (as used in DNS records; an address points to a name) PTR: Partner: PTR: Painter: PTR: Pupil/Teacher Ratio: PTR: Public ...
Read more

Testrealm (PTR) - Foren - World of Warcraft

Blizzard Entertainment benutzt Cookies und ähnliche Technologien auf ihren Webseiten. Wenn Sie weiter durch die Webseite browsen, nachdem Ihnen die Cookie ...
Read more

FAQ: Öffentlicher Testrealm - Blizzard-Kundendienst

Einkäufe auf dem PTR. Der öffentliche Testserver von Heroes of the Storm ermöglicht Ihnen, neue Produkte aus dem Shop zu kaufen und damit zu spielen.
Read more

PTR – Wikipedia

PTR ist eine Abkürzung für: Air Arabia Jordan, eine jordanische Fluggesellschaft (ICAO-Code) Paid to read, ein Geschäftsmodell; Physikalisch-Technische ...
Read more

Herzlich Willkommen bei PTR D, A, CH

Professionalität Bei PTR hat Professionalität einen sehr hohen Stellenwert: bei den PTR Pros stehen Professionalität, Toleranz und Respekt immer im ...
Read more

Reverse DNS lookup - Wikipedia, the free encyclopedia

Reverse DNS lookup In computer networking, reverse DNS lookup or reverse DNS resolution (rDNS ... Multiple PTR records can cause problems, however, ...
Read more