Electromagnetic Radiation Study Guide
Why are Gamma rays and X-Rays so dangerous to come into contact with?
Gamma rays and X-rays are both so high energy they can ionize atoms -that means they can violently rip electrons away from atoms - which can make them dangerous.
Radio waves have the longest wavelengths of all electromagnetic waves. a. True b. False
a. True
When light travels from water to air, its speed a. increases b. decreases c. stays the same
a. increases
Which of the following electromagnetic wavelengths would have the highest frequency? a. 100 m b. 10 m c. 1 m d. 0.1 m
d. 0.1 m
Red light has a frequency of 4.6 X 1014 Hz (460,000,000,000,000 Hz). What is the wavelength of red light?
0.000000652173913 meters
An electromagnetic wave has a frequency of 2 GHz (2,000,000,000 Hz). What is the wavelength of the wave?
0.15 meters
Compare/Contrast UVA, UVB, and UVC rays.
Compare/Contrast UVA, UVB, and UVC rays. Answer: There are many differences between UVA, UVB, and UVC rays. Ultraviolet A (UVA) waves have a wavelength between 400 and 315 nm. UVA rays account for 95% of the ultraviolet radiation that reaches Earth's surface. UVA rays are present with equal intensity at all daylight hours throughout the year and can penetrate both clouds and glass. It is the UVA rays that are the primary reason skin will "tan". Tanning is the body's defense against further damage to DNA caused by UVA rays. Ultraviolet B (UVB) waves have a wavelength between 315 and 280 nm. The intensity of UVB rays varies depending on time of day, year, and location. In the United States, UVB rays are at their highest intensity from 10 AM to 4 PM during the months of April to October. UVB are more intense at higher elevations and on reflective surfaces, such as snow or ice. UVB rays do not penetrate glass. Ultraviolet C (UVC) waves have a wavelength between 280 nm and 100 nm. Most UVC rays are absorbed by Earth's atmosphere and do not reach the surface of Earth.
Electromagnetic Spectrum:
Electromagnetic radiation is organized by how much energy it carries. The range of electromagnetic radiation is the Electromagnetic spectrum.
How do electromagnetic waves differ from mechanical waves?
Electromagnetic waves do not need a medium to travel through while mechanical waves do.
Why is it impossible for human beings to see infrared and ultraviolet light?
Humans can't see infrared and UV light because it doesn't fall in the wavelength spectrum. We can only see between 390 and 700 nanometers and infrared and UV light have longer wavelengths than that, therefore, we cannot see infrared and UV light.
In relation to the "normal", when light passes from air to water at an incident angle of 90 degrees, where will the light diffract to?
In relation to the normal, light does not change directions when the angle of incidence is 90 degrees.
Explain how a radio works, including its parts, as well as the difference between AM and FM radios.
Radio waves have two parts, a transmitter and a receiver. The transmitter encodes information onto a wave by changing a property of the wave. It then sends the wave out through an antenna. A radio receives the signal when the antenna of the receiver picks up the wave. The receiver then decodes the information contained on the wave and turns the wave into a mechanical wave.The mechanical wave is amplified with an amplifier and vibrates speakers accordingly.There are two ways to change the property of the wave that is sent out by the transmitter: Amplitude Modulation (AM) and Frequency Modulation (FM). AM (Amplitude Modulation) occurs when the amplitude (height) of the wave is changed. When the receiver detects the signal, it is decoding the change in the amplitude of the waves that were transmitted. This is different from Frequency Modulation. FM (Frequency Modulation) occurs when the frequency of the wave is changed. When the receiver detects the signal, it is decoding the change in the frequency of the waves that were transmitted. Both AM and FM waves undergo slight changes in amplitude as they travel. Since AM stations send information by changing amplitude, each additional change in amplitude is heard as static. Since FM stations send information by changing frequency, the radio simply filters out any changes in amplitude. This leads to a clear station with no static.
List the following electromagnetic waves in order of decreasing wavelength (increasing energy) - Gamma Rays, Microwaves, Radio Waves, Visible Light Waves, Ultraviolet Waves, X-Ray Waves, and Infrared Waves.
The electromagnetic waves in order of decreasing wavelength are: Radio, Microwaves, Infrared, Visible Light, Ultraviolet, X-rays, and Gamma Rays.
As electromagnetic waves travel, they do not lose energy. True or False
True
Explain how we perceive an object's color.
We see an object at a certain color because all the other color are absorbed except for the certain color. For example, if white light shines on the flowers, all wavelengths of light are absorbed except yellow, which is reflected away and received by the eye.
How does a prism work?
White light can be separated into colored light if it passes through transparent matter, such as a prism, at an angle. As the light passes through the material it slows down and bends. Because colored light waves have different wavelengths, they bend at different angles, creating the color spectrum.
X-Rays
X-ray (ray short for radiation) are EM waves that have .01nm-10nm. Shorter than ultraviolet light but longer than gamma rays. Discovered by Wilhelm Rontgen and are called "X"-rays due to his use of the letter "Z" to signify another unknown type of radiation. X-rays are emitted by electrons and have high energy levels which allow them to be used in the medical field for imaging.
How are X-Ray images captured?
X-rays are higher energy than light waves. Because of this, X-rays pass right through less dense material like soft tissues, but are absorbed by denser material like bones. X-rays are sent through the body part of interest to a film detector or sensor behind it. The X-rays that pass through soft tissues are exposed as dark areas on the detector. The X-rays that are absorbed by dense tissues (or metals) do not pass through, leaving those areas white on the sensor.
Microwave
an electromagnetic wave with a wavelength in the range 0.001-0.3 m, shorter than that of a normal radio wave but longer than those of infrared radiation. Microwaves are used in radar, in communications, and for heating in microwave ovens and in various industrial processes
How many primary colors are there in visible light? a. 2 b. 3 c. 4 d. 5
b. 3
Which of the following forms of electromagnetic radiation has the shortest wavelength? a. Visible light b. X-Ray c. Microwaves d. Radio waves
b. X-Rays
Which of the following waves in the visible light spectrum bends the most when it is refracted? a. Orange b. Yellow c. Violet d. Blue
c. Violet
The highest energy electromagnetic waves are a. radio waves b. visible light waves c. gamma rays d. x-Rays
c. gamma rays
If an object hit by white light appears green, which of the following colors of light must be absorbed by the object? a. Red b. Orange c. Yellow d. All of the above
d. All of the above
Infrared Light
discovered in 1800 by William Herschel when he conducted an experiment to see how the temperature of visible light changed based on color. Red was warmer than violet but that there was also a region beyond red light that was even hotter. This region of heat is known as the infrared region.
Transparent objects
do allow light to pass through. The wavelengths of light absorbed are determined by the object's pigments. The light that is transmitted is the color of light the eye sees.
Opaque objects
do not allow light to pass through them. They absorb most wavelengths of light that hit them, and reflect select wavelengths of light. The reflected wavelength of light is the color we see.
Gamma Rays
highest amount of energy. They have the shortest wavelength, and have the highest frequency. Gamma rays and X-rays are both so high energy they can ionize atoms that means they can violently rip electrons away from atoms which can make them dangerous.
Radio Wave
needs a transmitter and receiver. Has the longest wavelength in the electromagnetic spectrum.
Ultraviolet Radiation
shorter wavelength than visible light and is undetectable by human eyes. Some birds and insects can see some wavelengths in the UV range. Range from 10 nm-400 nm. Ultraviolet A (UVA) range from 315 nm-400 nm. UVA rays account for 95% of the ultraviolet radiation that reaches Earth's surface. Present at the same intensity all year. Can penetrate clouds and glass. Ultraviolet B (UVB) range from 280 nm-315 nm. The intensity depends on time of day, year, and location. In the United States, UVB rays are at their highest intensity from 10 AM to 4 PM during the months of April to October. UVB are more intense at higher elevations and on reflective surfaces, such as snow or ice. UVB rays do not penetrate glass. Ultraviolet C (UVC) range from 100nm-280nm. UVC are absorbed by Earth's atmosphere and do not reach the surface of Earth.
Radar
stands for Radio Detection and Ranging and it transmits microwaves
Electromagnetic Radiation
the movement of energy through space.
Visible Light
the only light that humans can see with a naked eye
Electromagnetic Radiation is produced by ________
the sun, light bulbs, and nuclear reactions
Reflection
waves bounce back off the matter.
Absorption
waves can be absorbed by the matter.
Refraction
waves pass through the matter at a different angle due to the wave's change in speed.
