CSET Practice Test on Waves

The typical rainbow diagram you often see depicts the
electromagnetic spectrum and its various regions. The
longer wavelength, lower frequency regions are located on
the far left of the spectrum and the shorter wavelength,
higher frequency regions are on the far right. Two very
narrow regions with the spectrum are the visible light
region and the X-ray region.

Electromagnetic radiation can be described in terms of a
stream of photons, each traveling in a wave-like pattern,
moving at the speed of light and carrying some amount of
energy. It was pointed out that the only difference
between radio waves, visible light, and gamma-rays is the
energy of the photons. Radio waves have photons with low
energies, microwaves have a little more energy than radio
waves, infrared has still more, then visible, ultraviolet,
X-rays, and gamma-rays.

Waves

A wave is a traveling disturbance that moves energy from
place to place.  Although different types of waves exist
(mechanical/electromagnetic; transverse/longitudinal),
they share basic characteristics that be used to describe
and compare waves.  If we look at a typical waveform,
three characters become apparent,  amplitude, wavelength
and frequency (image).

Amplitude is the maximum measure of displacement of the
medium by the wave.  It can be the highest point of a
crest or the lowest point of a trough.  Because amplitude
is a distance measure, any metric unit of length or
distance is appropriate for amplitude (m, cm, mm, etc.).
Wavelength is also a distance or length measure.  It is
the length of a single wave in the waveform.  Since
wavelength is constant in a waveform, you can measure the
distance between any two identical points on adjacent
waves to find the wavelength - peak of crest to peak of
crest, for instance.  Wavelength may also be appropriately
reported in any metric unit for length.

Frequency is a measure of how many waves pass a stationary
point in a unit of time.  In the above figure, three waves
are present.  If these three waves passed a stationary
point in one second, the frequency would be 3 waves/sec.
We also use the unit Hertz (Hz) to report frequency
values.  One wave/sec is equal to one Hz; the wave in the
above figure can be said to have a frequency of 3 Hz.

Amplitude, wavelength and frequency of a wave can give us
some idea about the amount of energy being carried by the
wave.  For waves with equal wavelengths and frequencies,
the larger the amplitude, the more energy being carried.
Energy is required to set matter in motion.  The more
motion or displacement of the matter, the more energy
present.  For waves with equal amplitudes, shorter
wavelengths and higher frequencies are associated with
greater energy.  It requires more energy to cause a faster
vibration in the medium.  For electromagnetic waves, for
instance, ultraviolet light and gamma rays have very high
frequencies and very short wavelengths.  They carry a
large amount of energy.  Infrared rays and radio waves
have lower frequencies and longer wavelengths - they carry
less energy.

Source: Ms. C's GMHS Science Website