REVIEW SHEET FOR ASSESSMENT #1 FOR 2nd QUARTER

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KNOW HOW TO READ AND INTERPRET THE ELECTROMAGNETIC SPECTRUM CHART BELOW

REMEMBER…..ROY G. BIV(red, orange, yellow, green, blue, indigo, violet is visible light)

What is the electromagnetic spectrum?

Answer:The electromagnetic spectrum is the entire range of electromagnetic energy. A small portion of the electromagnetic spectrum is visible light, or colors. Other forms of electromagnetic energy travel around us all of the time, but our eyes cannot see those frequencies. When an object reflects all colors of visible light, (or absorbs none) white is produced. When an object absorbs all colors of visible light, (or reflects none) black is produced.

How does the color of light relate to its frequency and wavelength?

Answer: For electromagnetic waves, the frequency and wavelength of the wave are inversely related. This means that waves with low frequency have a longer wavelength, and waves with high frequency have a shorter wavelength. The color of light is determined by the frequency of the light wave. Red light is the lowest frequency (longest wavelength) light and violet light has the highest frequency (shortest wavelength).

How does the surface of a material affect the color of a material?

Answer:When light strikes an opaque surface, the surface will absorb some frequencies of light and reflect others. When light is absorbed, heat is absorbed.The frequency a surface absorbs and reflects is determined by the chemical makeup of the surface. The frequency of light that is reflected from a surface determines the color of that material. In other words, the color of an object is the color that is reflected by the object. White objectsreflect all frequencies of all the colors…therefore the object appears white (white light). On the other hand black objectsabsorb all frequencies of all colors…therefore the object appears black (all the colors mixed together).

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  • Explain how we see the red color on an object and no other color.

Answer: The reason why an object is red is that due to the chemical make-up of the object, it absorbs the frequencies of all other color but it reflects the frequency of red.

SOUND & ELECTROMAGNETIC WAVES

  • The major properties of waves are:

wavelength

frequency

amplitude

crest

trough

  • A waveis a disturbance that transfers energy
  • Sound is a longitudinalwave that is produced by a vibrating object and travels through matter.
  • Longitudinal waves transfer energy by compressions and rarefactions (opposite of compressions).
  • Electromagnetic waves are transverse waves that are produced by a combined disturbance of electrical and magnetic fields and travels through empty space.
  • Transverse waves transfer energy perpendicular (or at right angles to the disturbance.
  • A wave that transfers energy or travels through matter is called a mechanical wave.
  • A wave that transfers energy or travels through empty space is called radiation.
  • All electromagnetic waves areradiation.
  • All electromagnetic waves are also a part of the electromagnetic spectrum (EMS).
  • The medium of a wave is the means by which the energy is transferred in the wave.
  • The medium of an electromagnetic wave is empty space.
  • The medium of a mechanical wave is matter of any kind.
  • The most common medium of a sound wave is air, although sound can travel through solid objects such as metal and liquids such as water.
  • The disturbances that produce sound waves are called vibrations.
  • Sound reflection is called an echo.
  • SoundWavestransfer energy primarily through the air.
  • Sound travels faster in solids (metal) than it does in liquids (water) and faster in liquids than it does in gases (air). Hence, sound travels the fastest through solids, the slowest through gases, in between through liquids.
  • The higher the pitch of a sound, the higher the frequency of the sound wave.

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