5 Written questions
5 Matching questions
- When white light passes through a cool cloud of gas, we see
A) visible light.
B) infrared light.
C) thermal radiation.
D) an absorption line spectrum.
E) an emission line spectrum.
- No object produces a perfect thermal radiation spectrum, but many objects produce close approximations. Which of the following would not produce a close approximation to a thermal radiation spectrum?
A) a hot, thin (low-density, nearly transparent) gas
B) a filament in a standard (incandescent) light bulb
C) a star
- The following questions refer to the diagram below. The levels represent energy levels in a hydrogen atom. Each level is labeled with its energy (above the ground state of Level 1) in units of electron/volts (eV). The labeled transitions represent an electron moving between energy levels.
1) Which transition represents an electron that absorbs a photon with 10.2 eV of energy?
2) Which transition represents the electron that emits a photon with the highest energy?
3) Which transition represents an electron that is breaking free of the atom?
4) Which transition, as shown, is not possible?
- You observe the same spectral line in two stars that are identical in every way except that one rotates faster than the other. How does the spectral line differ between the two?
A) There is no difference.
B) The line in the faster rotating star is blueshifted.
C) The line in the faster rotating star is redshifted.
D) The line in the faster rotating star is broader.
E) The line in the faster rotating star is narrower.
- 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.
- a A) a hot, thin (low-density, nearly transparent) gas
- b E) X rays travel through space faster than radio waves.
- c D) The line in the faster rotating star is broader.
- d 1) B
- e D) an absorption line spectrum.
5 Multiple choice questions
- E) a trillion times greater.
- A) An electron begins in an excited state and then gains enough energy to jump to the ground state.
- A) The two spectra would have similar shapes, except Neptune's spectrum would be missing a big chunk of the red light that is present in the Sun's spectrum.
- C) The wavelengths of spectral lines in the star's spectrum.
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. → A) Electrons orbit the nucleus rather like planets orbiting the Sun.
Thermal radiation is defined as
A) radiation produced by a hot object.
B) radiation in the infrared part of the spectrum.
C) radiation that depends only on the emitting object's temperature.
D) radiation in the form of emission lines from an object.
E) radiation that is felt as heat. → C) radiation that depends only on the emitting object's temperature.
An atom which has 4 protons and 6 neutrons will be electrically neutral if it contains ________.
A) 4 electrons
B) 6 electrons
C) 10 electrons
D) at least one electron → A) 4 electrons
The most common isotope of gold has atomic number 79 and atomic weight 197. How many protons and neutrons does the gold nucleus contain? Assuming the gold is electrically neutral, how many electrons does it have? If the gold is triply ionized, how many electrons does it have? → The most common isotope of gold contains 79 protons and 118 neutrons. If it is neutral, it also contains 79 electrons. If the gold is triply ionized instead, it is missing 3 electrons and so has only 76 electrons.
Which of the following statements is true of green grass?
A) It absorbs red light and emits green light.
B) It absorbs red light and reflects green light.
C) It transmits all colors of light except green.
D) It means the lawn is healthy. → B) It absorbs red light and reflects green light.