An accurate measurement of the fundamental spin-spin relaxation time (t2) comes from the amplitude of the "spin echo" as a function of delay time (t). the experiment involves a 900 pulse that rotates the spins into the x-y plane, where they precess at a range of frequencies due to the range of local fields. after the delay time t, a 180° pulse is applied so that the spins that were ahead by precessing faster are inverted to become behind the spins that precessed slower. a large-amplitude spin echo occurs at an additional delay of t, when the faster precessing spins temporarily coincide with the slower precessing spins. question 1 2 pts when the delay time between the 900 and 1800 pulses is t-5.66 ms, the spin echo (that occurs at a later time) becomes 1/e of its initial amplitude. the resulting spin-spin relaxation time is t2 d question 2 2 pts the table (pasted below) gives the amplitudes of the spin echo as a function of the delay time between 90° and 180° pulses. fitting the data to an exponential r delay(ms) 0.2 0.5 echolv) 4024 3.786 3.364 2.791 2.239 1.868 1.725 1.152 0.838 0.462 7.5 10 15 elaxation function yields a spin-spin relaxation time of ta ms

Acetic acid  /əˈsiːtɪk/, systematically named  ethanoic acid  /ˌɛθəˈnoʊɪk/, is a colourless liquid  organic compound  with the  chemical formula  ch3cooh (also written as ch3co2h or c2h4o2). when undiluted, it is sometimes called  glacial acetic acid.  vinegar  is no less than 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. acetic acid has a distinctive sour taste and pungent smell. in addition to household vinegar, it is mainly produced as a precursor to  polyvinyl acetate  and  cellulose acetate. it is classified as a  weak acid  since it only partially  dissociates  in solution, but concentrated acetic acid is corrosive and can attack the skin.acetic acidnamespreferred iupac nameacetic acidsystematic iupac nameethanoic acidother namesvinegar (when dilute); hydrogen acetate; methanecarboxylic acid[1][2]identifierscas number64-19-7  3d model (jsmol)interactive image3dmetb00009 reference506007chebichebi: 15366  chemblchembl539  chemspider171  drugbankdb03166  echa infocard100.000.528ec number200-580-7e numbere260  (preservatives)gmelin reference1380iuphar/bps1058keggd00010  meshacetic+acidpubchem  cid176rtecs numberaf1225000uniiq40q9n063p  un number2789inchiinchi=1s/c2h4o2/c1-2(3)4/h1h3,(h,3,4)  key:   qtbsbxvteameqo-uhfffaoysa-n  smilescc(o)=o

The radiation of the fire causes the saucepan to heat up. the conduction of the saucepan then to distribute the heat over the saucepan and to give heat to the water. the convection of the water distributing the heat within the water, till all the water is boiling

Molybdeum(mo)orruthenium (ru)actually, elements with similar chemical properties as technetium would bemn, re, and bh. this is because elements in the same group/family (column) have similar chemical properties. elements in the same period (row) have the same number of energy levels (or shells).

Each student aligns the edge of the object with the left edge of the ruler as shown above. all four students read the ruler with a measurement of 4.6 cm. which statement describes the data they collect? i believe the answer is: the data have poor precision and poor accuracy because of a systematic error.