What is a type of wave that can travel through empty space to transfer energy?
Repeating disturbances that transfer energy through matter or space.
If the frequency of a water wave changes, with constant velocity, what else must also change?
What type of electromagnetic radiation is heat energy?
Why does silver have a lower resistance to electron flow than iron?
the nuclei holds electrons more loosely.
Equation to figure velocity
v=wavelength x frequency
Equation to figure wavelength
wavelength= velocity / frequency
Which waves have the lowest energy?
If the wavelength of a given wave decreases, you know that its frequency will.......
What kind of waves produce heat (thermal energy)?
How can the elements present in a star be determined?
By analyzing the light of a star's spectrum
A wave will travel as long as it has..........
energy to carry.
How is the energy a wave carries measured?
By its frequency
How is an electromagnetic wave produced?
When a charged object accelerates.
What does an electromagnetic wave consist of?
----vibrating at RIGHT angles
What kind of waves NEED a medium to travel through?
What 3 things are in a cathode ray tube and what is the purpose of each?
Cathode- negatively charged device that sends out electrons
Magnet- Magnetic field that focuses and guides the beam of electrons
Coated screen- Glows when hit by electrons to produce the picture
What is used to kill bacteria on medical supplies?
Global Positioning System-----A system of satellites, ground monitoring stations, and receivers
How are changing electric and magnetic fields related?
They produce each other
What kind of energy does electromagnetic waves carry?
A method in which police use radio waves to detect speeders.
As the frequency of an electromagnetic wave increases, the speed of the wave......
stays the same.
The entire range of electromagnetic frequencies
a particle of light. Light can behave as a particle
What is a cell phone?
Device that transmits one radio signal and receives another radio signal at the same time, allowing a cordless phone user to talk and listen at the same time. Can send and receive messages.
What is a pager?
Can only receive messages.
Which frequencies are lower, AM or FM?
What part of the electromagnetic spectrum is usually used for communication?
Why are gamma rays dangerous?
Because they break down molecules and cells
What does your body need to make vitamin D?
Which has a higher frequency, purple (violet) light or yellow light?
Which electromagnetic radiation has the shortest wavelength?
What is the particle that carries radiant energy?
What kind of waves are electromagnetic waves?
What is the speed of electromagnetic waves in a vacuum?
What do television satellites use to transmit?
What do CFCs or chlorofluorocarbons destroy?
the ozone layer
layer of the stratosphere with a high concentration of ozone; absorbs most of the Sun's harmful ultraviolet radiation
What are the most energetic electromagnetic waves?
The amount of energy a photon carries is determined by its .......
Defend this statement. "Light has both a wave and a particle nature."
Light has all the properties of waves like refraction, diffraction, and interference. However, its energy depends upon frequency not amplitude which is like a particle.
Describe the ozone layer and explain why it is necessary for our health.
The ozone layer is high in our atmosphere. It absorbs most of the sun's harmful UV waves.
What are UVA and UVB? How are they alike and how are they different?
UVA- longer wavelength UV waves UVB-shorter wavelength UV. Both damage skin and can cause cancer and wrinkles. UVB causes sunburn.
How are sound waves and radio waves the same? How are they different?
Both are created by vibrations, experience refraction, diffraction, interference. Sound are compressional waves that need a medium. Radio are transverse waves and do not require a medium.
Why is a satellite telephone not convenient for two-way conversations?
Because of the great distances the signal must travel to and from the satellite, there can be annoying delays in the conversation.
Describe how a radio wave reaches your ear. 7 steps
1. The radio wave sent from the radio station is picked up by your antenna. 2. The electrons vibrate providing a signal with information. 3. An amplifier boosts the signal and sends it to speakers. 4. The speakers vibrate 5. This causes a compressional wave which moves through the air. 6. Air molecules vibrate and send it to your ear. 7. The ear and brain interprets the sound.