AST 101 CH 5 EXAM QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE 2026

AST 101 CH 5 EXAM QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE 2026 Thermal radiation is defined as _________. - Answers radiation with a spectrum whose shape depends only on the temperature of the emitting object Suppose you look at a spectrum of visible light by looking through a prism or diffraction grating. How can you decide whether it is an emission line spectrum or an absorption line spectrum? - Answers An emission line spectrum consists of bright lines on a dark background, while an absorption line spectrum consists of dark lines on a rainbow background. Which of the following best describes the fundamental difference between two different chemical elements (such as oxygen and carbon)? - Answers They have different numbers of protons in their nucleus. Suppose you know the frequency of a photon and the speed of light. What else can you determine about the photon? - Answers its wavelength and energy Which of the following statements best describes the two principle advantages of telescopes over eyes? - Answers Telescopes can collect far more light with far better angular resolution. Suppose you watch a leaf bobbing up and down as ripples pass it by in a pond. You notice that it does two full up and down bobs each second. Which statement is true of the ripples on the pond? - Answers They have a frequency of 2 hertz. If we say that a material is opaque to ultraviolet light, we mean that it _________. - Answers absorbs ultraviolet light According to the laws of thermal radiation, hotter objects emit photons with _________. - Answers a shorter average wavelength Suppose you want to know the chemical composition of a distant star. Which piece of information is most useful to you? - Answers the wavelengths of spectral lines in the star's spectrum The stars in our sky twinkle in brightness and color because of _________. - Answers turbulence in Earth's atmosphere Refer to the numbered features on the below graph, which is a schematic spectrum of the planet Mars. - Answers ... Which of the six numbered features represents emission lines? - Answers 1 Which of the six numbered features represents absorption lines? - Answers 5 Which portion(s) of the spectrum represent(s) reflected sunlight? - Answers 2,3 & 4 What does the wavelength of the peak labeled 6 tell us about Mars? - Answers its surface temperature What feature(s) of this spectrum indicate(s) that Mars appears red in color? - Answers the fact that the intensity of region 4 is higher than that of region 2 In hydrogen, the transition from level 2 to level 1 has a rest wavelength of 121.6 nm. - Answers ... Find the speed for a star in which this line appears at wavelength 120.4 nm . - Answers vv = 2960 km/s Find the direction for a star in which this line appears at wavelength 120.4 nm . - Answers toward us Find the speed for a star in which this line appears at wavelength 121.1 nm . - Answers 1230 km/s Find the direction for a star in which this line appears at wavelength 121.1 nm . - Answers toward us Find the speed for a star in which this line appears at wavelength 121.9 nm . - Answers 740 km/s Find the direction for a star in which this line appears at wavelength 121.9 nm . - Answers away from us Find the speed for a star in which this line appears at wavelength 122.7 nm . - Answers 2710 km/s Find the direction for a star in which this line appears at wavelength 122.7 nm . - Answers away from us Some nitrogen atoms have seven neutrons and some have eight neutrons; these two forms of nitrogen are: - Answers isotopes of each other. Define atomic number and atomic mass number. - Answers Atomic number is number of protons. Atomic mass number is number of protons and neutrons. Under what conditions are two atoms different isotopes of the same element? - Answers Two atoms are different isotopes of the same element if they have different numbers of neutrons. The Hubble Space Telescope obtains higher-resolution images than most ground-based telescopes because it is: - Answers above Earth's atmosphere. A star whose spectrum peaks in the infrared is: - Answers cooler than our Sun. Assume the woman in the figure uses her prism to look at a spectrum of light coming from the object(s) shown. In which case will she see a continuous rainbow of thermal radiation? - Answers 1 In which case will the woman see a rainbow of color interrupted by a few dark absorption lines? - Answers 2 In which case will the woman see a just a spectrum that is almost entirely black except for few bright emission lines? - Answers 3 This photo shows the visible light spectrum of the Sun. Why does it have all those dark lines on it? - Answers The dark lines represent wavelengths of light at which atoms near the Sun's surface absorb radiation from the hotter solar interior. This figure shows idealized thermal radiation spectra from several stars and a human. Based on this graph, at about what wavelength does a 15,000 K star emit its most intense light? - Answers About 100 nanometers Consider the spectra of the four objects shown beneath the laboratory spectrum. Based on these spectra, what can you conclude about Object 1? - Answers It is moving away from us.