Electromagnetic Radiation
a type of heat radiation; the infrared light in sunlight, for example, is what makes the sunlight feel warm upon one's skin.
infrared light
what is the frequency of a wave if only one-tenth of it goes by in 1 second?
0.10 cycle
how is a hertz (Hz) defined?
1 cycle per second
based upon the inverse square law, how will the intensity of light change as the distance increases from 1m to 4m from the source?
1/16 as intense
which of the following is the speed of light?
300 million m/sec
if a wavelength of electromagnetic energy is 1/2 m, what is the frequency?
600 MHz
if light photons are stopped by a substance, the light is said to be:
absorbed
a particle that has two protons and two neutrons bound together, but no electrons.
alpha particle
which of the following has the longest wavelength?
am radio
the height of a wave is called:
amplitude
the height of a wave. a wave with a large amplitude is generally stronger than a wave with a small amplitude.
amplitude
the condition of light when some of the photons are absorbed but some are transmitted through a substance.
attenuated
what happens when an electron falls back into its normal lower shell? a. it emits energy b. a photon is released c. the atom returns to its normal state d. all of the above
d. all of the above
which of the following have photons? a. x-rays b. gamma rays c. visible light d. all of the above
d. all of the above
which of the following is true of all electromagnetic energy? a. it has photons b. it has varying levels of energy c. it moves at the speed of light d. all of the above
d. all of the above
electromagnetic energy is a combination of:
electric and magnetic fields
what is the range of wavelengths called that includes x-rays, radio waves, and visible light?
electromagnetic spectrum
x-ray originate in:
electron shells
as photons collide with body tissue, what part of body atoms can be broken from molecules?
electrons
in electromagnetic energy, what is vibrating?
energy itself
x-rays and gamma rays are different from light because they have:
enough energy to knock electrons out of atoms
the number of waves that go by in 1 second is called:
frequency
the number of waves that go by in a second.
frequency
x-rays can have differing amounts of energy because the amount of energy a photon has is proportional to its:
frequency
the amount of energy carried in a wave increases as the:
frequency increases
a type of electromagnetic radiation at the high end of the spectrum with a frequency greater than visible light and ultraviolet light.
gamma ray
the SI unit of measurement for frequency (abbreviated Hz)
hertz
what is the SI unit of measurement for frequency?
hertz
what occurs when something makes an electron jump to a higher shell?
it gains energy
which of the following is not true of all electromagnetic energy?
it has a constant frequency
A characteristic of photons is that they all have:
no mass
the property of a substance that totally absorbs light rays.
opaque
a particle of energy that has no mass; emitted as light or another form of electromagnetic energy.
photon
photoelectric cells convert sunlight into electricity when struck by a steady stream of:
photons
the property of a substance that allows x-rays to partially pass through it.
radiolucent
the property of a substance that does not allow x-rays to pass through it
radiopaque
x-rays cannot pass through lead because it is:
radiopaque
the bending of light photons as they pass through one clear medium to another.
refraction
the bending of light rays through a prism is called:
refraction
the wave form of electromagnetic energy, the wave having regular characteristics such as a constant amplitude and wavelength.
sine wave
x-rays are generally attenuated by:
soft tissue
approximately 3x10^8 m/sec, or 300 million meters per second. all electromagnetic radiation travels at the same velocity through space.
speed of light
the longer the wavelength:
the lower the frequency
gamma rays originate in:
the nucleus
frequency is determined by:
the number of waves in 1 second
the property of a substance that partially absorbs, or attenuates, light rays.
translucent
the state of light photons that have passed through a substance such as air, clear glass, or the near vacuum of space
transmitted
electromagnetic energy in a vacuum would normally:
travel in a straight line
as an unstable atom of a radioactive element naturally decays into a more stable state, it emits at that moment of decay a photon of energy and:
two protons and two neutrons
energy at a higher frequency that can interact with molecules in one's skin and cause sunburn or, over a long term, skin cancer.
ultraviolet light
which of the following has the highest frequency?
ultraviolet light
waves in the electromagnetic spectrum all travel at the same ___________, the speed of light, or 300 million meters per second.
velocity
what does frequency times wavelength equal?
velocity
which of the following has the shortest wavelength?
visible light
a property of energy created by the vibrations of photons. it can be compared to a ripple that moves water molecules up and down on the surface of a pond.
wave
the length of one wave, measured from the top of one wave to the top of the next. ________=velocity/frequency
wavelength
the measurement from the top of one wave to the top of the next is called:
wavelength
what does velocity divided by frequency equal?
wavelength
frequency rises as the:
wavelength shortens
