Selected Key Terms Scientific A system for representing any number as a notation number between 1 and 10 times a power of ten. Exponent The number to which a base is raised. Engineering A system for representing any number as a one-, notation two-, or three-digit number times a power of ten with an exponent that is a multiple of three. Metric prefix A symbol that is used to replace the power of ten in numbers expressed in scientific or engineering notation. Scientific and Engineering Notation Very large and very small numbers are represented with scientific and engineering notation. This eliminates leading and trailing zeros. 47,000,000 = 4.7 x 107 (Scientific Notation) = 47. x 106 (Engineering Notation) Scientific Notation In scientific notation, each quantity is expressed as a product of a positive number (usually between 1 and 10) and a power of ten. The power of ten is expressed as an exponent of base 10. Scientific Notation 1 0 7 = 1 0 ,0 0 0 ,0 0 0 1 0 6 = 1 ,0 0 0 ,0 0 0 1 0 5 = 1 0 0 ,0 0 0 1 0 4 = 1 0 ,0 0 0 1 0 3 = 1 ,0 0 0 102 = 100 1 01 = 1 0 100 = 1 1 0 − 1 = 0 .1 1 0 − 2 = 0 .0 1 1 0 − 3 = 0 .0 0 1 1 0 − 4 = 0 .0 0 0 1 Scientific Notation Numbers (less than one) are expressed in scientific notation with negative powers of ten. .0035 = 3.5 x 10-3 Large numbers (greater than one thousand) are expressed in scientific notation with positive powers of ten. 3500 = 3.5 x 10+3 Scientific Notation 0.000027 = 2.7 x 10-5 0.605 = 6.05 x 10-1 8300 = 8.3 x 10+3 756000 = 7.56 x 10+5 Rules for Calculating Addition requires that all added numbers be expressed in the same power of ten. Convert numbers so they have the same power of ten. Then add the numbers without their powers of ten to get the sum. The power of ten of the sum is the same as for the added numbers. (1 × 105 ) + (2 × 105 ) = (1 + 2 ) × 105 = 3 × 105 (3.7x10-5) + (62x10-6) = (37x10-6) + (62x10-6) = (37+62) x 10-6=99x10-6 Rules for Calculating Subtraction also requires that all numbers be expressed in the same power of ten. Subtract the numbers without their powers of ten to get the difference. The power of ten of the results is the same as for the individual numbers. (25 × 10−6 ) − (130 × 10−7 ) = (250 × 10−7 ) − (130 × 10−7 ) = = (250 − 130) × 10− 7 = 120 × 10− 7 Rules for Calculating Multiplication does not require any prior calculations. The numbers are multiplied directly without their powers of ten. Then the powers of ten must be added algebraically. ( 3 × 10 6 ) × ( 2 × 10 4 ) = ( 3 × 2 ) × 106 + 4 = 6 × 1010 Rules for Calculating Division does not require any prior calculations. The numbers are divided directly without their powers of ten. Then the power of ten of the denominator is subtracted algebraically from the power of ten of the numerator. 3 8 10 (8 × 103 ) ÷ (4 × 10 2 ) = × 2 = 2 × 103− 2 = 2 × 101 4 10 Engineering Notation Engineering notation is an application of SCIENTIFIC NOTATION in which the powers of ten are limited to the multiples of three such as 103; 109; 10-6;10-3. The reason for this is that in engineering and technology all units are expressed with prefixes that symbolize relevant powers of ten. These are called metric prefixes Engineering Metric Prefixes 1015 peta P 1015 1012 tera T trillion 109 giga G billion 106 mega M million 103 kilo k thousand Engineering Metric Prefixes 10-3 milli m one-thousandth 10-6 micro µ one-millionth 10-9 nano n one-billionth 10-12 pico p one-trillionth 10-15 femto f femto Engineering Notation 0.000027 = 27 x 10-6 = 27 0.605 = 605 x 10-3 = 605m 8300 = 8.3 x 10+3 = 8.3k 756000 = 756 x 10+3 = 756k 0.0285 = 28.5 x 10-3 = 28.5m Metric Conversions When converting from a larger unit to a smaller unit, move the decimal point to the right. Remember, a smaller unit means the number must be larger. Smaller unit 0.47 MΩ = 470 kΩ Larger number Metric Conversions When converting from a smaller unit to a larger unit, move the decimal point to the left. Remember, a larger unit means the number must be smaller. Larger unit 10,000 pF = 0.01 µF Smaller number Quiz Scientific and Engineering Notation 1. a. b. c. d. Express in scientific notation: 77200 7.72 × 104 7.72 × 10–7 772 × 102 7.72 × 10–4 2. a. b. c. d. Express in scientific notation: 0.000447 4.47 × 104 447 × 106 4.47 × 10–4 447 × 10–6 3. a. b. c. d. Express in decimal notation: 2.58 × 105. 0.000258 258000 0.000000258 25800 Quiz Scientific and Engineering Notation 4. a. b. c. d. Express in decimal notation: 9.09 × 10–4 9090 0.00909 0.000909 90900 5. a. b. c. d. Express in decimal notation: 29300 µs 29.3 s 29300000 s 29300 s 0.0293 s 6. a. b. c. d. Express in decimal notation: 552 ms 0.552 s 0.000552 s 55200000 s 552000 s Quiz Scientific and Engineering Notation 7. a. b. c. d. Express in decimal notation: 91.6 k meters (km) 0.0916 meters 0.0000916 meters 91600 meters 91600000 meters 8. a. b. c. d. Express in decimal notation: 22.9 Mm 0.0000229 m 0.0229 m 22900 m 22900000 m 9. a. b. c. d. Express in engineering notation: 88200 meters 88.2 µm 88.2 mm 88.2 km 88.2 Mm Quiz Scientific and Engineering Notation 10 . a. b. c. d. Express in engineering notation: 0.000771 meters 771 mm 771 µm 771 km 771 Mm 11 . a. b. c. d. Convert to engineering notation. 11.8 × 10–4 meters 118 mm 1.18 Mm 1.18 km 1.18 mm 12 . a. b. c. d. Convert to engineering notation. 63.9 × 104 meters 6.39 mm 639 km 63.9 km 639 mm Quiz Scientific and Engineering Notation 13 . a. b. c. d. Evaluate: 2.3 × 103 + 0.42 × 104 = 6.5 × 104 6.5 × 103 650 65000 14 . a. b. c. d. Evaluate: 7800 µA + 0.23 mA = 10.1 µA 8.03 mA 8.03 µA 10.1 mA 15 . a. b. c. d. Evaluate: (2.2 x 10-9)(7 x 10-6) 15.4 x 10-3 9.2 x 10-3 1.54 x 10-14 5.2 x 10+15
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