The Nature of Em Waves
is a transverse wave that transfers electrical and magnetic energy
Electromagnetic waves
longest wavelength
lowest frequency
Radio waves
All waves of the EM spectrum travel at this speed.
What is the speed of light?
This type of radio signal is called AM. For what do these letters stand?
Amplitude Modulation
Why is it dangerous to leave a pet in your car during the summer?
The Greenhouse effect.
Which is faster, gamma rays or radio waves?
Neither. They both travel at the speed of light (300,000 km/sec or about 186,000 miles/sec.). Their frequencies and wavelengths are much different, but all portions of the EM spectrum travel at the speed of light.
2nd longest wavelength
2nd lowest freguency
microwaves
The electric portion of the EM spectrum induces what?
the magnetic portion
This type of radio signal is called FM. For what do these letters stand?
Frequency Modulation
Passing light through a _______ will cause the various colors of the rainbow to spread out.
prism
Light that reflects off objects vibrate in only one plane because it is __________.
Polarized light
between microwaves and visible light
Between visible light and x rays
Infrared rays
Ultraviolet rays
The magnetic portion of the EM spectrum induces what?
the electric portion
When under a bridge, __ signals can be heard, but not __.
and
Why?
FM AM
and
Because FM waves have a higher frequency, bu shorter waves (~ 3 m), so they an bounce around under the bridge. AM signals are about 300m and too long totransmit under that bridge.
What protects us from something which comes from the sun which would damage our atmosphere?
Our magnetic field ... from the solar wind.
When light shines on some substances it causes electrons to flow. This is called the ___________ effect. Who described it for his Nobel prize?
Photoelectric effect, and Albert Einstein.
2nd shortest wavelength
2nd highest frequency
x rays
The doppler effect for light.
Why is this significant?
what is the red shift?
Because it proves that the universe is expanding.
Gps stands for
and
Our cell phones are based on whose theory?
Global positioning system
and
On Einstein's general law of relativity. Without it our positioning would drift about 6 or 7 miles per day!
. Without these corrections, satellite clocks would run about 38 microseconds faster than clocks on Earth daily, causing cumulative errors that would make navigation apps and precise timing systems useless within hours. The error is not static; it builds rapidly, with positioning errors accumulating at roughly 11 km/day (7 miles /day).
What is the solar wind?
A continuous stream of charged particles (ions and electrons) from the sun traveling at over 1 million mph.
A packet of light energy
Photon
shortest wavelength
highest frequency
Gamma rays
How do we know that the universe is expanding?
and
Name one of the two people who used ________'s field equations to predict this.
red shift - the Doppler effect for light.
and
Georges Lemaitre and Edwin Hubble used Einstein's field equations to predict this effect and the expansion of our universe.
(Einstein did not accept it at first because it required a Creator, but was convinced by Hubble.)
How do engineers pre-compensate for satellite clocks which would run about 38 microseconds faster once in orbit?
Engineers pre-compensate by setting satellite clocks to run slightly slower before launch, matching the speed they will have once in orbit. This avoids an error of about 11.4 km/day (~ 7 miles/day).
About what percent of our energy comes from the sun?
About 99.98%