EDITOR'S COLUMN Quantity Dynamic viscosity
SI Unit Symbol newtonNs/m 2 sec. per sq. meter Work, energy joule J Power watt W Electric coulomb C charge Voltage volt V Electric volt per V/m field meter strength Electric ohm Ω resistance Electric farad F capaci tance Magnetic weber Wb flux Inductance henry H Magnetic tesla Τ flux density Magnetic ampere per A/m field meter strength Magnetoampere A motive force Light flux lumen Im Luminance candela per cd/m 2 sq. meter Illuminalux Ix tion
Tn the International System there is only one unit for each quan tity, although multiples and submultiples of each unit may be designated by the prefixes approved by the 11th General Conference on Weights and Measures. The In ternational Committee on Weights and Measures added the two pre fixes, atto and femto, at its annual meeting in 1962. [Nat. Bur. Std. (U. S.), Tech. News Bull. 47, 29 (1963)]. The complete table of préfixes is given below. Multiples and Submultiples 10 1 2 10» 10" 10 3 102 10 10" 1 10 -10~3 10 ~6 10 ~9 ΙΟ" 1 2 10- 15 10~18
PROBLEM SAMPLES? NO PROBLEM WITH THE CARY MODEL 15 SPECTROPHOTOMETER
The spectra illustrate the excellent performance of the Model 15 not only with a sample (CS2) under ideal conditions, but also with a small, dense, prob lem sample (Naphthalene). For Model 15 details, ask for Data File A308-54.
Small volume samples (0.5 cc) easily accommodated with the 3x10 mm beam size of the Model 15. Large samples conveniently handled as well as heated cells, cryostats, and cells up to 100 mm length in spacious (5%" L χ 5 > f W χ 5%" D) sample compartment of Model 15. •
Prefixes Symbols tera Τ giga G mega M kilo k hecto h deka da deci d centi c milli m micro μ nano η pico ρ femto f alto a
Dense or highly absorbing samples are read directly, time-consuming dilutions avoided. Low stray light (0.001% over most of range) and photometer design allow direct read ing to 3.4 Abs. High photometric accuracy of the Cary Model 15 over entire absorbance range eliminates need to adjust sample absorbance for optimum accuracy. APPLIED PHYSICS CORPORATION 2 7 2 4 SOUTH PECK ROAD • MONROVIA. CALIFORNIA
INSTRUMENTS Raman.'UV//R
Circle No. 171 on Readers' Service Card •
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Cary®
Recording Spectrophotometers · Vibrating Reed Electrometers
