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PPT – Electromagnetic Waves PowerPoint presentation | free to view - id: 7d47c3-NjkyZ

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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.

http//www.monos.leidenuniv.nl/smo/basics/images/

wave.gif

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!

http//micro.magnet.fsu.edu/primer/java/speedofli

ght/javalightspeedfigure1.jpg

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.

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Scientific Notation

- Removes extra zeros from numbers to make them

smaller. - Example
- 300,000,000. m/s
- 3.0 x 108 m/s

Scientific Notation

- Move decimal to the left positive exponent.
- 23,000,000.
- Left 7 spaces
- 2.3 x 107

Scientific Notation

- Move decimal to the right negative exponent.
- 0.0000067
- 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 104) x (4.0 x 103)
- 12.0 x 107 , but the mantissa is bigger than 10

so. - 1.2 x 108

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 107) / (4.0 x 103)
- 0.5 x 104 , but the mantissa is less than 1 so
- 5.0 x 103

Scientific Notation Calculators

Scientific Notation Calculators

- Graphing or 2-line (6.67 x 10-11)

- Enter 6.67

- Press the EE Key

- Enter -11

- 6.67 x 10-11

Scientific Notation Calculators

- One Line (3.71 x 10-5)

- Enter 3.71

- Press the EE Key or EXP Key

- Enter -5

- 3.71 x 10-5

Scientific Notation Calculators

- For both calculators, when entering negative

exponents use the negative key not the minus

sign key!!!