Light Basics
What is the speed of light in empty space?
3000,000 km/sec
What part of the electromagnetic spectrum can humans see?
Visible Light Spectrum
What temperature scale is used in many physical sciences?
Kelvin
What two main things do telescopes improve compared to the human eye?
light-gathering power and resolving power
After light is collected, what must happen next?
it must be detected and recorded
What are the two main models of light?
Wave and Particle
What visible color has the shortest wavelength?
Violet
What is 0 K called?
Absolute Zero
What type of telescope uses a lens?
refractor
What kind of telescope detects radio waves?
radio telescope
What is a particle of light called?
Photon
What visible color has the longest wavelength?
Red
As an object gets hotter, does it radiate more strongly at longer or shorter wavelengths?
shorter wavelengths
What type of telescope uses a mirror
reflector
What kind of telescope can detect hot gas around black holes?
X-Ray
What does wave-particle duality mean?
light can be described as both a wave and a particle
As wavelength decreases, what happens to energy?
it increases
As an object heats up, what color shift can happen?
red toward yellow and blue
Which is more widely used today by astronomers: refractors or reflectors?
reflectors
Why are false-color images used?
to show wavelengths humans cannot see
What is the difference between brightness and color?
brightness is the total amount of energy/intensity; color is determined by wavelength
Why can UV light cause sunburn but infrared usually does not?
Uv Carries more energy
Why is Kelvin used instead of Celsius in many science settings?
because it is directly tied to energy and molecular motion and has no negative temperatures
Why do astronomers often describe a telescope by the diameter of its lens or mirror?
because bigger detecting area means more light-gathering power
Why must some telescopes be placed in space?
because some wavelengths cannot penetrate Earth’s atmosphere