# National Aeronautics and Space Administration

## Gamma-Ray Bursts - Electromagnetic Notation

### ELECTROMAGNETIC NOTATION

Scientific notation is used when dealing with very large numbers such as 43,000,000 or very small numbers such as .000043. Scientific notation allows us to write these numbers and work with these numbers without the cumbersome job of dealing with so many digits. In scientific notation, forty-three million becomes 4.3 x 107 simply by moving the decimal 7 places to the left. Numbers less than one require the decimal to be moved to the right so forty-three millionths becomes 4.3 x 10-5. Notice the exponent is negative when the decimal is moved to the right while the exponent is positive when the decimal is moved to the left. Remember that with scientific notation only one digit should be in front of the decimal.

The electromagnetic spectrum is an arrangement of electromagnetic radiation according to wavelength, frequency, or energy level. The spectrum ranges from radio waves, which are low-energy, low-frequency, long waves, to gamma-rays, which are the high-energy, high-frequency, short waves. Listed in order below are the components of the electromagnetic spectrum. Beside each type of radiation you will find the length of a wave in meters which falls into that radiation type. A wavelength is the distance from one crest or trough to the next crest or trough. Convert these numbers to scientific notation by moving the decimal to the left or the right.

1. gamma-rays .0000000000001 m

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2. X-rays .0000000001 m

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3. ultraviolet rays .00000001 m

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4. visible light .0000005 m

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5. infrared rays .00001 m

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6. microwaves .01 m

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The number of waves that pass a particular point in a given amount of time is the wave frequency. Each component of the electromagnetic spectrum has its own frequency range. The unit on a wave's frequency is a Hertz, or wave per second. Listed below are the components of the electromagnetic spectrum. Beside each type of radiation is a frequency value expressed in scientific notation which falls in the range of that radiation type. Convert the scientific notation into standard form by moving the decimal the appropriate number of places to the left or the right.

8. gamma-rays 1 x 1021 Hertz

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9. X-rays 1 x 1018 Hertz

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10. ultraviolet rays 1 x 1016 Hertz

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11. visible light 5 x 1014 Hertz

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12. infrared rays 1 x 1013 Hertz

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13. microwaves 1 x 1010 Hertz

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14. radio waves 1 x 105 Hertz

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 A service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Andy Ptak (Director), within the Astrophysics Science Division (ASD) at NASA/GSFC