5 Written questions
5 Matching questions
- 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.
- Suppose you are listening to a radio station that broadcasts at a frequency of 97 Mhz (megahertz). Which of the following statements is true?
A) The radio waves from the radio station are causing electrons in your radio's antenna to move up and down 97 million times each second.
B) The radio waves from the radio station have a wavelength of 97 million meters.
C) The "radio waves" received by your radio are not light waves like those we talk about in astronomy, but rather are a special type of sound wave.
D) The radio station broadcasts its signal with a power of 97 million watts.
- Grass is green because it absorbs green light, reflecting all other colors.
- If a material is transparent, then it
A) reflects light well.
B) absorbs light well.
C) transmits light well.
D) scatters light well.
E) emits light well.
- Suppose you built a scale-model atom in which the nucleus is the size of a tennis ball. About how far would the cloud of electrons extend?
A) a few meters
B) several centimeters
C) several kilometers
D) to the Sun
- a A) The radio waves from the radio station are causing electrons in your radio's antenna to move up and down 97 million times each second.
- b C) several kilometers
- c False
- d C) transmits light well.
- e C) The passage of a light wave can cause electrically charged particles to move up and down.
5 Multiple choice questions
- B) Atom 1: nucleus with 7 protons and 8 neutrons, surrounded by 7 electrons;
Atom 2: nucleus with 7 protons and 7
- C) a molecule containing two or more elements
- B) a shorter average wavelength
- The ice melts into liquid, then evaporates into gas. At higher temperatures, the water molecules dissociate atoms. At very high temperatures, the atoms are ionized.
- A) radiation with a spectrum whose shape depends only on the temperature of the emitting object
5 True/False questions
If a material is highly opaque, then it
A) reflects most light.
B) absorbs most light.
C) transmits most light.
D) scatters most light.
E) emits most light. → C) transmits light well.
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.
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
D) you → B) a shorter average wavelength
The study of energy levels in atoms is called
A) special relativity.
B) general relativity.
C) quantum mechanics.
D) classical mechanics.
E) particle physics. → False
You observe a distant galaxy. You find that a spectral line normally found in the visible part of the spectrum is shifted toward the infrared. What do you conclude?
A) The galaxy is moving away from you.
B) The galaxy is moving toward you.
C) The galaxy has very weak gravity.
D) The galaxy is made purely of hydrogen.
E) The composition of the galaxy is changing. → A) The star is moving toward us.