Study Guide: Exam #3
Our solar system is moving away from a group of three stars. Star A is a blue star that is slightly closer than the other two. Star B is a red star that is the farthest away in the group. Star C is a yellow star halfway between the other two stars. Which describes the doppler shift from the group of stars?
All three stars are redshifted
This astronomer discovered the relationship between the intrinsic brightness of cephid variable stars and the time they take to vary in brightness, making it possible for others to estimate the distance of these faraway stars, and estimate the distances to other galaxies.
Henrietta Leavitt
What happens to the light that is missing in an absorption spectrum?
It is absorbed by atoms in the cool, low density cloud and then re-emitted in all different directions as an emission spectrum.
Betelgeuse is the bright red star representing the left shoulder of the constellation Orion. All the following statements about Betelgeuse are true. Which one can you infer from its red color?
Its surface is cooler than the surface of the Sun.
Why does the planet Mars appear red?
Mars reflects visible light from the Sun, but the rocks on Mars' surface absorb most of the blue light, so the light that reflects is mostly red.
An asteroid that is moving farther away from the sun is gaining
Potential energy.
Which of the following has the lowest frequency?
Radio Waves
Which of the following would be true about comparing gamma rays and radio waves?
Radio waves would have a longer wavelength and travel the same speed as gamma rays.
Star A gives off the same amount of energy as Star B, but Star A has much more surface area than star B. Which star has the greater temperature?
Star B
Which of the following statements best describes the two principle advantages of telescopes over eyes?
Telescopes can collect far more light with far better angular resolution.
Which of the following has the higher temperature?
The metal filament that produces light in a regular white light bulb.
Which of the following forms of electromagnetic radiation travels the slowest?
They all travel at the same speed
A metal sewing pin and a large iron bar are heated so that they both glow the same red color. Which of the following is true for these two objects?
They are both at the same temperature, but the iron bar radiates more energy than the metal pin
The Chandra X-ray Observatory must operate in space because
X-rays do not penetrate Earth's atmosphere
If an electron in an atom moves from an energy level of 5eV to an energy level of 2eV,
a photon of energy 3eV is emitted.
A sodium street light uses electricity to heat up sodium gas (vapor), and produces yellow light. What type of spectrum does this produce?
an emission spectrum with bright emission lines in the yellow part of the spectrum
The spectra of most galaxies show redshifts. This means that their spectral lines...
have wavelengths that are longer than normal
Which of the following wavelengths can be observed most easily by a telescope located on Earth's surface?
radio waves
The Hubble Space Telescope has revolutionized astronomy with its 2.4 meter mirror. This achievement is due to its significantly better compared to Earth-based telescopes.
resolving power
The stars in our sky twinkle in brightness and color because of
turbulence in Earth's atmosphere.
Compared to an atom as a whole, an atomic nucleus is:
very tiny, and has most of the mass.
