Term
| A gas heated to millions of degrees would emit |
|
Definition
|
|
Term
| An atom of the element iron has an atomic number of 26 and an atomic mass number of 56. If it is neutral, how many protons, neutrons, and electrons does it have? |
|
Definition
| 26 protons, 30 neutrons, 26 electrons |
|
|
Term
|
Definition
| an amount of energy much smaller than a joule |
|
|
Term
| Compared to the size of its nucleus, the size of an atom is about |
|
Definition
| one hundred thousand times greater |
|
|
Term
| Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons. What is its atomic number and atomic mass number? |
|
Definition
| The atomic number 79 and the atomic mass number is 197 |
|
|
Term
| Currently the largest optical telescope mirrors have a diameter of |
|
Definition
|
|
Term
| Everything looks red through a red filter because |
|
Definition
| the filter transmits red light and absorbs other colors |
|
|
Term
| From laboratory measurements we know that a particular spectral line formed by hydrogen appears at a weavelength of 121.6 nm. The spectrum of a particular star shows the same hudrogen line appearing at a wavelenght of 121.8 nm. what can we conclude? |
|
Definition
| The star is moving away from us. |
|
|
Term
| From lowest energy to highest energy, rank the different categories of electromagnetic radiation. |
|
Definition
| RADIO INFRARED VISIBLE LIGHT ULTRAVIOLET X-RAYS GAMMA RAYS |
|
|
Term
| How are wavelength, frequency, and energy related for photons of light? |
|
Definition
| Longer wavelenght means lower frequency and lower energy |
|
|
Term
| How can an electron in an atom lose energy to go from a higher energy level to a lower energy level? |
|
Definition
| It releases a photon equal in energy to its own energy drop |
|
|
Term
| How do we estimate the surface temperature of a star? |
|
Definition
| By optaining its spectrum and classifying the spectral type (color0 |
|
|
Term
| How many atoms fit across the period at the end of this sentence?` |
|
Definition
|
|
Term
| If a material is transparent then it |
|
Definition
|
|
Term
| if we observe one edge of a planet to be redshifted and the opposite edge to be blueshifted, what can we conclude about the planet |
|
Definition
|
|
Term
| If you heat a gas so that collisions are continually bumping electrons to higher energy levels, when the electrons fall back to lower energy levels, the gas produces |
|
Definition
| an emission line spectrum |
|
|
Term
| Imagine a planet like Earth orbiting the Sun, but in an orbit with an average distance of 2 AU. What is the orbital period |
|
Definition
|
|
Term
| In what part of the electromagnetic spectrum do the biggest telescopes on on Earth operate |
|
Definition
|
|
Term
| In what wavelenght range was interferometry first routinely used |
|
Definition
|
|
Term
| Spectra from neutral atoms compared with spectra from ionized atoms of the same element |
|
Definition
| have different sets of spectral lines |
|
|
Term
| suppose you see two stars: a blue star and a red star. Which of the following can you conclude about the two stars. Assume that no Doppler shifts are involved (Hint: Think about the laws of thermal radiation) |
|
Definition
| The blue star has a hotter surface temperature than the red star |
|
|
Term
| The energies of two photons you might detect emitted by hydrogen atoms are 10.2 and 2.1 eV. Which photon has the longest wavelength. |
|
Definition
|
|
Term
| The largest effective telescope, created by radio interferometry, is the siz of |
|
Definition
|
|
Term
| The frequency of a wave is |
|
Definition
|
|
Term
| The wavelength of a wave is |
|
Definition
| The distance between two adjacent peaks and the wave |
|
|
Term
| We are measuring the spectra of two hydrogen gas clouds. The laboratory frame wavelength of one hydrogen line is 656.2 nm. Cloud A's emission line wavelength is 660.1 nm and Cloud B's emission line wavelength is 670.1 nm. What can we conclude about these clouds? |
|
Definition
| They are both receding from us, and Cloud B is receding faster than Cloud A. |
|
|
Term
| We can see each other in the classroom right now because we |
|
Definition
|
|
Term
| When an atom loses an electron, it becomes |
|
Definition
|
|
Term
| When an electron in an atom goes from a higher energy state to a lower energy state, the atom |
|
Definition
| emits a photon of a specific frequency. |
|
|
Term
| Which of the following is not a way light and matter interact? |
|
Definition
|
|
Term
| Which of the following is not a good reason to place observatories on remote mountain tops? |
|
Definition
| to be able to observe at radio wavelengths |
|
|
Term
| Which of the following objects is not a close approximation of a thermal emitter? |
|
Definition
|
|
Term
| Which of the following statements about X-rays and radio waves is not true? |
|
Definition
| Neither X-rays nor radio waves can penetrate Earth's atmosphere. |
|
|
Term
| Which of the following statements about electrical charge is true? |
|
Definition
| A positive charge and a negative charge will attract each other. |
|
|
Term
| Which of the following statements about electrons is not true? |
|
Definition
| Electrons orbit the nucleus rather like planets orbiting the Sun. |
|
|
Term
| Which of the following statements about thermal radiation is always true? |
|
Definition
| A hot object emits photons with a higher average energy than a cool object. |
|
|
Term
| Which of the following wavelength regions cannot be studied with telescopes on the ground? |
|
Definition
|
|
Term
| Why do astronomers need different telescope designs to observe across the electromagnetic spectrum? |
|
Definition
| Photons of different energy behave differently and require different collection strategies. |
|
|
Term
| Without telescopes or other aid, we can look up and see the Moon in the night sky because it |
|
Definition
|
|
Term
| You and I are emitting primarily |
|
Definition
|
|
