POWERS OF TEN

1
POWERS OF TEN

• power of 10
• means 10 raised to some number e.g. 102
  10 ? 10 105 10 ? 10 ? 10 ? 10 ? 10 10n
  n factors of 10 n exponent
• scientific notation
• express numbers as a ? 10n , where a is a
  number of order 1 (i.e. between 1 and 10)
• negative exponent 10-n means 1/(10n)
• to multiply two powers, add their exponents
  102 ? 105 107
• thousand 103 , million 106
• common prefixes used to denote powers of ten
• kilo (k) 103 ,
• Mega (M) 106 ,
• Giga (G) 109
• Tera (T) 1012
• milli (m) 10-3 ,
• micro (?) 10-6
• nano (n) 10-9
• pico (p) 10-12

2
Units

• Metric units
• apart from few exceptions, metric units, or
  rather SI units are used throughout the world
  (SI stands for Système International,
  maintained by the Societé Internationale des
  Poids et Mesures, international society of
  weights and measures, with seat in Sèvres near
  Paris)
• basic units are, e.g. meter for distance,
  kilogram for mass, second for time
• meter originally defined as 1/(4 ? 107) ? length
  of Earth's meridian now defined in terms of
  speed of light
• some common distance units
• kilometer, km 103 m,
• centimeter, cm 10-2 m,
• millimeter, mm 10-3 m,
• micrometer, µm 10-6 m,
• nanometer, nm, 10-9 m
• metric vs English distance units
• 1 km ? 0.62 mi, 1mi ? 1.6 km,
• 1 m ? 3.3 ft ? 39 in,
• 1cm ? 0.39 in, 1 in 2.54 cm