5 Written questions
5 Matching questions
- Which of the following objects is not a close approximation of a thermal emitter?
A) hot, thin gas
B) a star
C) a filament in a light bulb D) you
E) a planet
- The spectra of most galaxies show redshifts. This means that their spectral lines
A) always are in the red part of the visible spectrum.
B) have wavelengths that are longer than normal.
C) have wavelengths that are shorter than normal.
D) have a higher intensity in the red part of the spectrum.
E) have normal wavelengths, but absorption of light makes them appear red.
- Emission lines from different ionization states of the same element appear in the same place in the spectrum
- Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons. If it is doubly ionized, what is the charge of the gold ion and how many electrons remain in the ion?
A) The gold ion has a charge of +2 and 77 electrons.
B) The gold ion has a charge of +2 and 79 electrons.
C) The gold ion has a charge of -2 and 77 electrons.
D) The gold ion has a charge of +2 and 2 electrons.
E) The gold ion has a charge of +79 and no electrons.
- The study of energy levels in atoms is called
A) special relativity.
B) general relativity.
C) quantum mechanics.
D) classical mechanics.
E) particle physics.
- a A) hot, thin gas
- b A) The gold ion has a charge of +2 and 77 electrons.
- c C) quantum mechanics.
- d B) have wavelengths that are longer than normal.
- e False
5 Multiple choice questions
- A) A hot object emits more radiation per unit surface area than a cool object.
- D) 81 times more energy.
- Every chemical element has a unique set of atomic energy levels and therefore a unique set of spectral lines. Thus, by identifying spectral lines, we can identify the elements that produced them.
- A) The star is moving toward us.
5 True/False questions
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) molecules go from the solid phase to the gas phase.
What is the name given to 2H?
D) tritium → C) deuterium
Which of the following best describes why we say that light is an electromagnetic wave?
A) Light can be produced only by electric or magnetic appliances.
B) Light is produced only when massive fields of electric and magnetic energy collide with one another.
C) The passage of a light wave can cause electrically charged particles to move up and down.
D) The term electromagnetic wave arose for historical reasons, but we now know that light has nothing to do with either electricity or magnetism. → C) The passage of a light wave can cause electrically charged particles to move up and down.
An atom in an excited state contains more of what type of energy than the same atom in the ground state?
B) kinetic energy
C) thermal energy
D) gravitational potential energy
E) electric potential energy → D) 81 times more energy.
Briefly explain how we can use spectral lines to determine an object's rotation rate. → Every chemical element has a unique set of atomic energy levels and therefore a unique set of spectral lines. Thus, by identifying spectral lines, we can identify the elements that produced them.