Electromagnetic Waves in a Nutshell

Electromagnetic Waves Unit Waves are very important because they transfer energy.

Low Frequency High Frequency Electromagnetic Spectrum is the scientific name for radiation. Radiation is energy emitted from waves (light) or from photons (particles) Low Frequency High Frequency

Radio waves- Are used to give you tunes in your car Radio waves- Are used to give you tunes in your car. Our the longest and weakest wave length. Are also released by stars or gases in the universe…They help scientists discover what the stars are made of! Microwaves- much smaller in length (3 mm) is also invisible. Allows you to pop popcorn but also used to study the universe and communicate with satellites that orbit earth. Infrared- thought of as “heat” but much of the heat rarely reaches earth. Help astronomers figure out the dust (gases) between stars.

Visible- Things we can see such as light bulbs and fireflies…ranging from red (longest wave light of visible to violet- shortest wave length of visible) Ultraviolet- Our atmosphere blocks most of this but this is what causes your skin to burn. Stars and other hot objects in space have UV rays. X-ray- Your doctor uses them to look at your bones but hot gases in the universe also emit x-rays. Gamma Rays- Radioactive materials some natural some man-made cause gamma rays. The biggest producer of gamma rays is the universe.

Crest- The sections that rise above the undisturbed line Trough- The sections that lie below the undisturbed line.

Amplitude- Is the positive or negative displacement from the normal line.

Wavelengths- The wavelength of a wave is the distance between any two adjacent corresponding locations on the wave train. This distance is usually measured in one of three ways:crest to crest, trough to trough or from the start of one wave cycle to the next.

Reflection and Refraction Refraction- is when waves are deflected when the waves go through a substance. The wave generally changes the angle of its general direction. Reflection- Is when waves bounce from a surface back toward the source. A mirror reflects the image of the observer.

1. Visible light can have different colors because it can have different: Frequencies Wavelengths Energies All of the above 45

2. Of the waves listed, which one has the longest wavelength? Microwave Radio waves X-rays Visible light waves 30

3. Electromagnetic energy invisible to the human eye is the: Yellow light Red light Blue light Ultraviolet light 45

4. The bending of light rays that results as light crosses a boundary from one substance to another. Reflection Diffraction Absorption Refraction 45

5. Wavelength of a wave is defined as: The distance from crest to crest One half the distance from crest to crest The distance between the highest and lowest point. How often a wave goes up and down. 45

6. If the light from a star is redshifted the astronomers: The star is moving away from the viewer. The star is moving toward the viewer. The star is not moving The star is a red giant. 45

Which part of the Electromagnetic spectrum has a frequency lower than visible light? X-ray Ultraviolet Infrared Gamma 45

8. How does gamma radiation compare to the energy of radiowaves? More energy Less energy Same amount Gamma is the speed of light. 45

9. Why is it safer for a pregnant woman to get an ultrasound instead of an x-ray? Ultrasound machines are smaller and use less energy The energy in an ultrasound is directed in one spot. X-rays have the same wavelength as radio waves X-rays have higher energy and may damage the fetus. 45

10. Which type of radiation can be stopped by a sheet of paper? Alpha Beta Gamma X-ray 45