9.3 Electromagnetic Waves

Question 1

Light as an electromagnetic wave

Answer 1

• Light is electromagnetic meaning that electromagnetic waves are produced by the motion of electrically charged particles, these waves are also called “electromagnetic radiation” because they radiate from the electrically charged particles

Question 2

Answer 2

Question 3

Types of Electromagnetic Waves (EMGS)

Answer 3

• Radio waves can be trasmitted over very long distances, around the earth’s surfaces by reflection form layers in the atmosphere
• Microwaves range from 1mm to 10cm, cook food and allow computers to communicate
• Infared waves or heat radiation is how you feel warmth. All objects that are not at a temperature of absolute zero radiate EMR, the hotter the object the more radiation is emitted
• Ultraviolet Waves (UV) have wavelengths shorter than violet light, cannot be seen with the naked eye. Causes skin cancer with increased exposure
• X-ray waves, produced by fast-moving electrons fired into an atom, can pass through body tissue and allow for an image to be taken
• Gamma-ray waves, highest energy, smallest wavelength radiation, produced in the nucleus of an atom, extremely penetrating

Question 4

EMR

Answer 4

• The many forms of electromagnetic radiation are essentially the same, differing only in frequency and wavelength
• Energy carried by the EMR is proportional to the frequency. High-frequency short-wavelength gamma rays are at the high-energy end of the spectrum. Low-frequency long-wavelength radio waves carry the least energy.
• Humans have cells in the eyes, can respond to EMR of frequencies between 400THz and 800THz, these frequencies make up visible light (ROYGBIV)
• All EMR travel at the speed of light in a vacuum

Question 5

EMR Formula

Answer 5