Jessica Horn: Chapter 5 Quiz

Quiz

1. What is light? Light is an electromagnetic wave but also comes in individual "pieces" called photons. Each photon has a precise wavelength, frequency, and energy: The shorter the wavelength  the higher the frequency and energy. In order of decreasing wavelength, the forms of light are radio waves, microwaves, infrared, visible light, ultraviolet, x rays, and gamma rays.
2. What is matter? Ordinary matter is made of atoms, which are composed of protons, neutrons, and electrons.Atoms of different chemical elements have different numbers of protons. Isotopes of a particular chemical element all have the same number of protons but different numbers of neutrons. Molecules are made from two or more atoms.
3. How do light and matter interact? Matter can emit, absorb, transmit, or reflect light.
4. What are the three basic types of spectra? There are three basic types of spectra: a continuous spectrum, which looks like a rainbow; an absorption line spectrum, in which specific colors are missing from the rainbow; and an emission line spectrum, in which we see lines of specific colors against a black background.
5. How does light tell us what things are made of? Emission or absorption lines occur only at specific wavelengths that correspond to particular energy level transitions in atoms or molecules. Every kind of atom, ion, and molecule produces a unique set of spectral lines, so we can determine an object's composition by identifying these lines.
6. How does light tell us the temperatures of planets and stars? Objects such as planets and stars produce thermal radiation spectra, the most common type of continuous spectra. We can determine temperature from these spectra because hotter objects emit more total radiation per unit area and emit photons with a higher average energy.
7. How does light tell us the speed of a distant object? The Doppler effect tells us how fast an object is moving toward or away from us. Spectral lines are shifted to shorter wavelengths for objects moving toward us and to longer wavelengths for objects moving away from us.
8. How do telescopes help us learn about the universe? Telescopes allow us to see fainter objects and to see more detail than we can see with our eyes. Telescopes specialized to observe different wavelengths of light allow us to learn far more than we could from visible light alone. Light-collecting area describes how much light a telescope can collect, and angular resolution determines the amount of detail in telescopic images.
9. Why do we put telescopes in space? Telescopes in space are above Earth's atmosphere and not subject to problems caused by light pollution, atmospheric distortion of light, or the fact that most forms of light do not penetrate through the atmosphere to the ground.
10. How is technology revolutionazing astronomy? Technology makes it possible to build more powerful telescopes and to enhance the capabilities of existing telescopes. Two key technologies are adaptive optics, which can overcome the distorting effects of Earth's atmosphere, and interferometry, in which individual telescopes are linked in a way that allows them to obtain the angular resolution of a much larger telescope.