5 Written questions
5 Matching questions
- Which of the following statements about X rays and radio waves is not true?
A) X rays have shorter wavelengths than radio waves.
B) X rays and radio waves are both forms of light, or electromagnetic radiation.
C) X rays have higher frequency than radio waves.
D) X rays have higher energy than radio waves.
E) X rays travel through space faster than radio waves.
- At extremely high temperatures (e.g., millions of degrees), which of the following best describes the phase of matter?
A) a gas of rapidly moving molecules
B) a plasma consisting of positively charged ions and free electrons C) a gas consisting of individual, neutral atoms, but no molecules
D) a plasma consisting of rapidly moving, neutral atoms
E) none of the above (At these extremely high temperatures, matter cannot exist.)
- Briefly explain how we can use spectral lines to determine an object's rotation rate.
- When an atom absorbs a photon containing energy, any of the following can happen except which?
A) The atom becomes excited.
B) The atom is ionized.
C) An electron moves from an upper energy level to a lower one.
D) An electron moves from a lower energy level to an upper one.
- If one object has a large redshift and another object has a small redshift, what can we conclude about these two objects?
A) The one with the large redshift is moving toward us faster than the one with the small redshift.
B) The one with the large redshift is moving away from us, and the one with the small redshift is moving toward us.
C) The one with the large redshift is moving away from us faster than the one with the small redshift.
D) The one with the large redshift is hotter and therefore is putting out more radiation.
- a C) The one with the large redshift is moving away from us faster than the one with the small redshift.
- b E) X rays travel through space faster than radio waves.
- c Lines are wider for faster-rotating objects because parts of the object are rotating toward us and parts are rotating away from us.
- d B) a plasma consisting of positively charged ions and free electrons
- e C) An electron moves from an upper energy level to a lower one.
5 Multiple choice questions
- A) a hot, thin (low-density, nearly transparent) gas
- B) a shorter average wavelength
- A) absorbs ultraviolet light
5 True/False questions
Which of the following statements about electrons is not true?
A) Electrons orbit the nucleus rather like planets orbiting the Sun.
B) Within an atom, an electron can have only particular energies.
C) Electrons can jump between energy levels in an atom only if they receive or give up an amount of energy equal to the difference in energy between the energy levels.
D) An electron has a negative electrical charge.
E) Electrons have very little mass compared to protons or neutrons. → D) A positive charge and a negative charge will attract each other.
Studying a spectrum from a star can tell us a lot. All of the following statements are true except one. Which statement is not true?
A) The total amount of light in the spectrum tells us the star's radius.
B) The peak of the star's thermal emission tells us its temperature: hotter stars peak at shorter (bluer) wavelengths.
C) We can identify chemical elements present in the star by recognizing patterns of spectral lines that correspond to particular chemicals.
D) Shifts in the wavelengths of spectral lines compared to the wavelengths of those same lines measured in a laboratory on Earth can tell us the star's speed toward or away from us. → B) The peak of the star's thermal emission tells us its temperature: hotter stars peak at shorter (bluer) wavelengths.
Process of Science: I am doing science when I already know the answer to my scientific question and I am searching for evidence in the natural world strictly to support what I know. → False
The most common isotope of uranium is U-238, but the form used in nuclear bombs and nuclear power plants is U-235. Given that uranium has atomic number 92, how many neutrons are in each of these two isotopes? → The atomic number would still be 8 because the number of protons wouldn't change, but the atomic weight would increase to 18.
All of the following statements about the Sun's corona are true. Which one explains why it is a source of X rays?
A) The temperature of the corona's gas is some 1 to 2 million Kelvin. B) The corona lies above the visible surface of the Sun.
C) The corona's gas consists mostly of hydrogen and helium.
D) The corona's structure is largely shaped by magnetic fields. → A) The temperature of the corona's gas is some 1 to 2 million Kelvin.