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Electromagnetic Waves EM waves are created by vibrating electric charges. (electrons in atoms!) These do not need a medium because they travel by transferring energy between electric and magnetic fields.

Electromagnetic Waves These electric and magnetic fields continually create one another allowing for EM waves to exist. Click Here for a 3D EM Wave Demo [

EM Wave Properties The speed of an EM wave depends on the medium it is traveling through. As the medium becomes more dense, the speed decreases! [

EM Wave Properties In a vacuum, EM waves travel at 300,000,000 m/s. Air is 299,997,000 m/s so we will use 300,000,000 m/s for simplicity.

Scientific Notation Removes extra “zeros” from numbers to make them smaller. Example: 300,000,000. m/s 3.0 x 10 8 m/s

Scientific Notation Move decimal to the left = positive exponent. 23,000,000. Left 7 “spaces” 2.3 x 10 7

Scientific Notation Move decimal to the right = negative exponent Right 6 “spaces” 6.7 x 10 -6

Scientific Notation Calculations Multiplication Multiply the mantissas. Add the exponents. Mantissa must have only 1 number in front of the decimal.

Scientific Notation Calculations Example: (3.0 x 10 4 ) x (4.0 x 10 3 ) 12.0 x 10 7, but the mantissa is bigger than 10 so…. 1.2 x 10 8

Scientific Notation Calculations Division Divide the mantissas. Subtract the exponents. Mantissa must have only 1 number in front of the decimal.

Scientific Notation Calculations Example: (2.0 x 10 7 ) / (4.0 x 10 3 ) 0.5 x 10 4, but the mantissa is less than 1 so… 5.0 x 10 3

Scientific Notation & Calculators

Graphing or 2-line (6.67 x ) Enter 6.67 Press the EE Key Enter x Scientific Notation & Calculators

One Line (3.71 x ) Enter 3.71 Press the EE Key or EXP Key Enter x Scientific Notation & Calculators

For both calculators, when entering negative exponents use the “negative” key not the “minus sign” key!!!