Exam 2 Review (Hard HWQ, CQ, Practice Exam)
Power is the rate at which energy is used, so its units are a unit of energy divided by a unit of time (Remember that energy is measured in joules and powers is measured in watts, and 1 watt = 1 joule/s.)
1) What is the difference between energy and power? Power is measured in joules and energy is measured in watts. Power is used to describe energy of light, whereas the term energy has a broader meaning. There's no difference; energy and power are different names for the same thing. Power is the rate at which energy is used, so its units are a unit of energy divided by a unit of time
a hot, thin (low-density, nearly transparent) gas (Photons must be able to bounce randomly around inside an object to produce thermal radiation, and that is not the case with a thin cloud of gas.)
23) 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? you a hot, thin (low-density, nearly transparent) gas a star a filament in a standard (incandescent) light bulb
The ball's gravitational potential energy is greatest at the instant when the ball is at its highest point. (Gravitational potential energy is greater at for a larger height because the ball has a greater distance that it can fall (and it accelerates as it falls)
10) Suppose you kick a soccer ball straight up to a height of 10 meters. Which of the following is true about the gravitational potential energy of the ball during its flight? The ball's gravitational potential energy is always the same. The ball's gravitational potential energy is greatest at the instant when the ball is at its highest point. The ball's gravitational potential energy is greatest at the instant it returns to hit the ground. The ball's gravitational potential energy is greatest at the instant the ball leaves your foot
It would vaporize (evaporate) into a gas, then the molecules would dissociate into individual oxygen atoms, then the atoms would become increasingly ionized as you continued to raise the temperature.
11) Suppose you had molecular oxygen (O2) chilled enough so that it was in liquid form. Which of the following best describes the phase changes that would occur as you heated the liquid oxygen to high temperature? The liquid oxygen first would solidify. The solid would then vaporize (sublimate) into a gas, which would then become a plasma as the molecules lost their electrons, until finally it consisted of bonded pairs of oxygen nuclei stripped bare of any electrons. It would vaporize (evaporate) into a gas, then the molecules would dissociate into individual oxygen atoms, then the atoms would become increasingly ionized as you continued to raise the temperature. The liquid molecules would quickly dissociate into a liquid of individual oxygen atoms. These atoms would then vaporize (evaporate) into a gas, and then become ionized to make a plasma. It would vaporize (evaporate) into a gas, then the molecules would lose electrons until no electrons were left, then the molecules would dissociate into individual oxygen nuclei.
The water can transfer heat to your arm more quickly than the air. (The boiling water has a lower temperature (212°F or 100°C) than the air in the hot oven, but because it is much denser, heat is transferred to your arm at a higher rate due to the more frequent collisions between your arm and the water molecules)
11) Suppose you heat an oven to 400°F (about 200°C) and boil a pot of water. Which of the following explains why you would be burned by sticking your hand briefly in the pot but not by sticking your hand briefly in the oven? The molecules in the water are moving faster than the molecules in the oven. The water has a higher temperature than the oven. The water can transfer heat to your arm more quickly than the air. The oven has a higher temperature than the water
(c) A 100 g bullet fired at a speed of 300 mph
23) Which of the objects below has the greatest kinetic energy? (1 m/s =2.24 mph) (a) A 1 kg baseball traveling at 90 mph (b) A 2,000 kg car creeping along at 1 mph (c) A 100 g bullet fired at a speed of 300 mph
(a) it rotated faster.
24) The cloud of gas from which the Sun (and the solar system) formed, shrank over time. The cloud was initially rotating. As the cloud shrank, (a) it rotated faster. (b) it's rotation rate remained constant. (c) it rotated slower
An object on a bound orbit follows the same path around the Sun over and over, while an object on an unbound orbit approaches the Sun just once and then never returns
24) What is the difference between a bound orbit and an unbound orbit around the Sun? An object on a bound orbit follows the same path around the Sun over and over, while an object on an unbound orbit approaches the Sun just once and then never returns. An object on a bound orbit has a gravitational attraction to the Sun, while an object on an unbound orbit does not. A bound orbit is an orbit allowed by the universal law of gravitation, and an unbound orbit is not. A bound orbit is circular, while an unbound orbit is elliptical.
A hot object emits more radiation per unit surface area than a cool object. (This is part of the first law of thermal radiation (the Stefan-Boltzmann law).)
24) Which of the following statements about thermal radiation is always true? All the light emitted by hot object has higher energy than the light emitted by a cooler object. A hot object emits more radiation per unit surface area than a cool object. A cold object produces more total infrared and radio emission per unit surface area than a hot object. A hot object produces more total infrared emission than a cooler object.
Its surface is cooler than the surface of the Sun. (Red light has lower energy than yellow or white light, so the red color of Betelgeuse tells us that its peak thermal radiation comes at lower energy than the peak thermal radiation of the yellow/white Sun. A lower energy of peak radiation means a lower temperature.)
25) Betelgeuse is the bright red star representing the left shoulder of the constellation Orion. All the following statements about Betelgeuse are true. Which one can you infer from its red color? It is much more massive than the Sun. It is much brighter than the Sun. It is moving away from us. Its surface is cooler than the surface of the Sun.
It can be used to determine the masses of many distant objects. (We can apply Newton's version of Kepler's third law whenever we observe one object orbiting another; this is the primary way that we measure masses throughout the universe)
25) Why is Newton's version of Kepler's third law so useful to astronomers? It allows us to calculate distances to distant objects. It can be used to determine the masses of many distant objects. It tells us that more-distant planets orbit the Sun more slowly. It explains why objects spin faster when they shrink in size
Uranus
25) ___ is the planet with the most extreme seasons because it rotates on its side.
The temperature of the corona's gas is some 1 to 2 million Kelvin. (The corona produces high-energy light (x-rays) because of its high temperature)
26) All of the following statements about the Sun's corona are true. Which one explains why it is a source of X-rays? The corona's gas consists mostly of hydrogen and helium. The temperature of the corona's gas is some 1 to 2 million Kelvin. The corona's structure is largely shaped by magnetic fields. The corona lies above the visible surface of the Sun.
Unbound
26) Hyperbolic and parabolic orbits are ___ orbits, ones in which the light object is gravitationally attracted toward the heavier object, but the attraction is not strong enough to cause the light object's path to bend enough for it to make full loops around the heavier object.
This statement is false. She and the Space Station share the same orbit and will stay together unless they are pushed apart.
26) If an astronaut goes on a space walk outside the Space Station, she will quickly float away from the station unless she has a tether holding her to the station This statement is true. She and the Space Station have different orbits at the beginning and will move apart. This statement is false. She and the Space Station share the same orbit and will stay together unless they are pushed apart. This statement is true. She and the Space Station cannot share the same orbit and will move apart quickly. This statement is false. She and the Space Station have different orbits at the beginning but will stay together due to mutual gravity.
The star is moving toward us. (The wavelength is shifted from 486.1 to 486.0 nm, which means a shift to a shorter wavelength. A shorter wavelength means a shift to the blue end of the spectrum (a blueshift) so that the object is moving toward us)
27) Laboratory measurements show hydrogen produces a spectral line at a wavelength of 486.1 nanometers (nm). A particular star's spectrum shows the same hydrogen line at a wavelength of 486.0 nm. What can we conclude? The star is moving toward us. The star is moving away from us. The star is getting hotter. The star is getting colder.
Saturn
27) ___ is the least dense of all the planets.
Star X is moving away from us faster than Star Y. (The redshifts mean that both stars are moving away from us, and a larger redshift means a faster speed)
28) Suppose that Star X and Star Y both have redshifts, but Star X has a larger redshift than Star Y. What can you conclude? Star X is coming toward us faster than Star Y. Star X is moving away from us faster than Star Y. Star X is moving away from us and Star Y is moving toward us. Star X is hotter than Star Y. Star Y is moving away from us faster than Star X.
Oort cloud
28) The ___ is a large collection of comets surrounding our solar system.
The planet is rotating (We see a blueshift from the side rotating toward us and a redshift from the side rotating away)
29) 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? The planet is in the process of formation. The planet is in the process of falling apart. The planet is rotating. We must actually be observing moons orbiting the planet in opposite directions, not the planet itself.
Venus
29) ___ rotates backwards on its axis compared to its direction of travel about the Sun.
The total amount of light in the spectrum tells us the star's radius. (We cannot measure radius from a spectrum without additional information.)
30) Studying a spectrum from a star can tell us a lot. All of the following statements are true except one. Which statement is not true? The peak of the star's thermal emission tells us its temperature; hotter stars peak at shorter (bluer) wavelengths. We can identify chemical elements present in the star by recognizing patterns of spectral lines that correspond to particular chemicals. The total amount of light in the spectrum tells us the star's radius. Shifts in the wavelengths of spectral lines compared to the wavelengths of those same lines measured in a laboratory on Earth can tell us the star's speed toward or away from us.
Neap
30) ___ tides occur when the Sun, Earth, and Moon form a right angle and are characterized by only small differences between high and low tide.
The faster rotating star has wider spectral lines than the slower rotating star. (Fast rotation will widen spectral lines because there is a greater difference in the Doppler shift from the side of the star rotating toward us and the side rotating away from us.)
31) Suppose that two stars are identical in every way; for example, same distance, same mass, same temperature, same chemical composition, and same speed relative to Earth, except that one star rotates faster than the other. Spectroscopically, how could you tell the stars apart? The peak of thermal emission will be at a shorter wavelength for the faster rotating star than for the slower rotating star. The faster rotating star will have an emission line spectrum whereas the slower rotating star will have an absorption line spectrum. The faster rotating star has wider spectral lines than the slower rotating star. There is no way to tell the stars apart spectroscopically because their spectra will be identical
Mercury, Venus
31) ___ and ___ are the two terrestrial planets with no moons.
Pluto
32) ___ is classified as a dwarf planet for, among other reasons, its small size and highly erratic orbit.
a peak intensity located at shorter wavelength This is one of the two laws of thermal radiation, also called Wien's law: Hotter objects produce photons with higher average energy, which means the peak intensity is located at shorter average wavelength.
33) For an object producing a thermal spectrum, a higher temperature causes the spectrum to have ___________. a peak intensity located at longer wavelength more prominent emission lines more prominent absorption lines a peak intensity located at shorter wavelength
Because the peak wavelength of the spectrum depends on the temperature of the object producing the spectrum. (Notice that the word "thermal" comes from a Greek root meaning "heat.")
33) Most continuous spectra are examples of what we also call thermal radiation spectra. Why do we call them "thermal" spectra? Because the peak wavelength of the spectrum depends on the temperature of the object producing the spectrum. Because these spectra have shapes that resemble those of traditional thermometers. Because these spectra can be produced only by very hot objects with temperatures of thousands of degrees or more. Because thermal comes from a Greek root meaning "continuous."
Radiative energy is energy in the form of light. Sunlight and radio waves carry this form of energy.
18) Choose the correct definition and two examples of radiative energy. Radiative energy represent energy of many individual particles. Sunlight and molecules of liquid in a cup of hot coffee carry this form of energy. Radiative energy is energy in the form of light. Sunlight and radio waves carry this form of energy. Radiative energy represent energy of many individual particles. Sunlight and molecules of hot, raising up air carry this form of energy. Radiative energy is energy in the form of light. Sunlight and acoustic waves carry this form of energy
Electrical charge is a measure of how strongly something will interact with electromagnetic fields.
18) Choose the correct definition of electrical charge. Electrical charge is a measure of how far electromagnetic fields are from each other. Electrical charge is a measure of how strongly electromagnetic fields interact with each other. Electrical charge is a measure of how far is something from a source electromagnetic fields. Electrical charge is a measure of how strongly something will interact with electromagnetic fields.
b, c, e
19) As compared to a hot star, a cooler star emits light most strongly at a [ (a) shorter (b) longer ] wavelength ([ (c) lower (d) higher ] frequency) and appears [ (e) redder (f) bluer ] in color
Earth's orbit would be unaffected. (The force of gravity between Earth and the Sun, and hence the orbital distance and speed of Earth, depends only on the Sun's mass (and the Earth-Sun distance), not on the Sun's size.)
19) Suppose that the Sun shrank in size but that its mass remained the same. What would happen to the orbit of the Earth? The size of Earth's orbit would shrink, and it would take less than one year to orbit the Sun. Earth's orbit would expand, and it would take more than one year to orbit the Sun. Earth's orbit would be unaffected. Earth would change from a bound orbit to an unbound orbit and fly off into interstellar space
The cloud is cool and lies between you and a hot star. (Atoms or molecules in the cloud therefore absorb specific wavelengths of light from the hot star.)
22) Which of the following conditions lead you to see an absorption line spectrum from a cloud of gas in interstellar space? The cloud is cool and dense, so that you cannot see any objects that lie behind it. The cloud is visible primarily because it reflects light from nearby stars. The cloud is extremely hot. The cloud is cool and lies between you and a hot star
decreases by a factor of 9 (Gravity follows an inverse square law, so the force goes down with the square of the distance; in this case, increasing the distance by a factor of 3 causes the force to decrease by a factor of 3^2 = 9)
23) According to the universal law of gravitation, if you triple the distance between two objects, then the gravitational force between them __________. increases by a factor of 9 decreases by a factor of 3 increases by a factor of 3 decreases by a factor of 9
Because the strongest visible emission lines from hydrogen are red (As shown in the video, hydrogen clouds produce several visible emission lines, but the red lines are generally the strongest.)
33) Most interstellar clouds are made mostly of hydrogen (because hydrogen is the most common element in the universe). Why are these clouds usually dominated by the color red? Because hydrogen gas clouds produce a continuous, red spectrum. Because hydrogen emits only red light, and no light of other colors. Because red light passes more easily through space than other colors of light. Because the strongest visible emission lines from hydrogen are red
Kuiper belt
33) The ___ is a large region just beyond Neptune's orbit containing many comets.
absorption lines
34) 1. Carbon dioxide in Mars's atmosphere produces _________________ in the infrared portion of its spectrum.
Doppler effect
34) 2. The ___________ allows us to determine how fast Mars is moving toward or away from us.
emission lines
34) 3. Hot gas in Mars's upper atmosphere produces _____________ in the ultraviolet portion of its spectrum.
visible portion
34) 4. The color of Mars in our sky is determined by the ________________ of Mars's spectrum.
thermal radiation
34) 5. We determine Mars's surface temperature from the peak wavelength of the ______________ it emits.
the wavelengths of spectral lines in the star's spectrum (Different chemical elements and ions produce different sets of spectral lines.)
34) Suppose you want to know the chemical composition of a distant star. Which piece of information is most useful to you? the Doppler shift of the star's spectrum the peak energy of the star's thermal radiation the wavelengths of spectral lines in the star's spectrum whether the star's spectrum has more emission lines or more absorption lines
Earth
34) ___ is unusual in that its moon is large in comparison to the size of the planet.
Wavelength
35) The __ of a wave is the distance between adjacent crests or adjacent troughs in the wave.
Jupiter
36) Io, Europa, Ganymede, and Callisto are ___'s four largest satellites.
Mercury
37) The temperature differences between ___'s day and night side are very extreme.
Mars
38) ___ has no liquid water today but there is evidence that it existed in the distant past.
Saturn
39) Titan is the largest satellite of ___ and the second largest natural satellite in our solar system.
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
4) Suppose you are listening to a radio station that broadcasts at a frequency of 97 MHz (megahertz). Which of the following statements is true? The radio waves from the radio station have a wavelength of 97 million meters. 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. The radio station broadcasts its signal with a power of 97 million watts. 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
Neptune
40) Triton, the largest satellite of ___, is the only large moon in our solar system which has a retrograde orbit, meaning it rotates about the planet in the opposite direction of the planet's rotation
They have a frequency of 2 hertz. (Remember that hertz are units meaning "cycles per second.")
8) 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? They have a frequency of 2 hertz. They have a frequency of 4 hertz. We can calculate the wavelength of the ripples from their frequency. They have a wavelength of two cycles per second.
The Sun would rotate faster than it does now Angular momentum is the product mass velocity (of rotation) radius. Shrinking the Sun's radius does not affect its mass, so the rotational velocity must increase to keep angular momentum constant
9) Suppose the Sun were suddenly to shrink in size but that its mass remained the same. According to the law of conservation of angular momentum, what would happen? The Sun would rotate faster than it does now. The Sun's angular size in our sky would stay the same. This could never happen because it is impossible for an object to shrink in size without an outside torque. The Sun's rate of rotation would slow
(a) 9×10^16 Joules
A Joule is the amount of energy a 1-Watt light bulb gives off in one second (the standard units for the meter-kilogram-second system of units that we have been using). How much energy would be produced by the total conversion of 1 kg of material into energy? (For your information, the sun converts this much mass to energy in less than a billionth of a second!) (a) 9×10^16 Joules (b) 9×10^13 Joules (c) 9×10^10 Joules (d) 3×10^5 Joules
(d) last quarter
After a sun-drenched day Joe Beachcomber watches a crystalline tropical sunset and notices there are neap tides and he doesn't see any moon in the sky. The phase of the moon is (a) new (b) first quarter (c) full (d) last quarter
a, b, h
An astronomer equipped with a spectrograph observes the spectrum of an astronomical object. They note that the wavelength of one of the helium lines is longer than it would be if the object were at rest. Using the picture at right, which direction(s) could the object be moving relative to the astronomer? *view Question 11 picture for choices*
(c) 7.3
The James Webb Space Telescope (JWST), which has a diameter of 6.5-meters, collects __ times as much light as the Hubble Telescope (HST), which has a diameter of 2.4-meters. (a) 2.7 (b) 3.1 (c) 7.3 (d) 9.6
(d) 2 times as much
How much does a Helium atom weigh compared to a Hydrogen atom? (a) 4 times less (b) 2 times less (c) the same (d) 2 times as much
(c) the difference between its maximum and minimum speeds would increase.
If a planet's orbit suddenly became more elliptical, then (a) it would stop moving all together. (b) the difference between its maximum and minimum speeds would decrease. (c) the difference between its maximum and minimum speeds would increase. (d) the difference between its maximum and minimum speeds would not change. (e) None of these
(c) 11absorption line
If light from a blackbody passes through a cool cloud of gas and then into a spectroscope, what kind of spectrum will be observed? (a) continuous (b) emission line (c) 11absorption line
(b) farthest planet from the Sun.
Neptune is the (a) heaviest planet in our solar system. (b) farthest planet from the Sun. (c) hottest planet in the solar system. (d) largest planet in our solar system.
(d) 10 (mu)m, in the infrared
You are approximately a perfect thermal emitter (congratulations!). You are about 300 K. At what wavelength do you emit the most radiation? (An angstrom is a unit of length where 1 Å=10^-10 m=0.1 nm.) (a) 5 (mu)m, in the ultraviolet (b) 1000 Å (c) 0.5 mm (d) 10 (mu)m, in the infrared (e) 0.025 (mu)m, or 250 Å
--- Clicker Questions ---
--- Clicker Questions ---
--- Homework 4 Questions ---
--- Homework 4 Questions ---
--- Homework 5 Questions ---
--- Homework 5 Questions ---
the total temperature of the objects (To understand why temperature is not a conserved quantity, remember that temperature is a measure of only one type of energy (thermal energy, which is the kinetic energy of moving particles) and this energy can be converted into other types of energy. (Also, there's no clear way to find the "total temperature" of two objects.))
12) Suppose that two objects collide. Which of the following things is not necessarily the same both before and after the collision? (In other words, which quantity is not conserved according to the laws of physics?) the total energy of the objects the total momentum of the objects the total temperature of the objects the total angular momentum of the objects
Electrons orbit the nucleus rather like planets orbiting the Sun.
12) Which of the following statements about electrons is not true? An electron has a negative electrical charge. Electrons orbit the nucleus rather like planets orbiting the Sun. Within an atom, an electron can have only particular energies. Electrons have little mass compared to protons or neutrons. Electrons can jump between energy levels in an atom only if they receive or give up an amount of energy equal to the difference in energy between the energy levels.
His angular momentum must be conserved, so reducing his radius must increase his speed of rotation (Remember that angular momentum is related to an objects mass × velocity × radius. The skater's mass stays the same but pulling in his arms reduces his "radius," so his velocity or rotation must increase to keep his angular momentum constant.)
13) When a spinning ice skater pulls in his arms, he spins faster because __________. There is less friction with the air. There exists an unbalanced reaction force. There is less friction with the ice. His angular momentum must be conserved, so reducing his radius must increase his speed of rotation
They have different numbers of protons in their nucleus. (Atomic number is the number of protons, and each chemical element has a different atomic number.)
13) Which of the following best describes the fundamental difference between two different chemical elements (such as oxygen and carbon)? They have different numbers of electrons. They have different numbers of protons in their nucleus. They have different atomic mass numbers. They have different names
4 electrons (The 4 electrons have a negative charge equal to the positive charge of the 4 protons, making the atom electrically neutral.)
14) An atom which has 4 protons and 6 neutrons will be electrically neutral if it contains __________. at least 1 electron 10 electrons 6 electrons 4 electrons
the average kinetic energy of particles in a substance (For example, air molecules are moving faster on average on a hot day than on a cool day)
14) What does temperature measure? the average kinetic energy of particles in a substance the average mass of particles in a substance the total amount of heat in a substance the total potential energy of particles in a substance
The angular momentum is the same at all four points This is the case because angular momentum is conserved throughout the orbit
15) The diagram shows a planet at four positions in its orbit. At which position does it have the greatest angular momentum? *view image in HW* 1 2 3 4 The angular momentum is the same at all four points
An electron begins in an excited state and then gains enough energy to jump to the ground state. (This is not possible because an excited state always has a higher energy than the ground state, which is the lowest possible energy level for an electron)
15) Which of the following transitions within an atom is not possible? An electron begins in the ground state and then gains enough energy to jump to an excited state. An electron begins in an excited state and then gains enough energy to become ionized. An electron begins in an excited state and then gains enough energy to jump to the ground state. An electron begins in the ground state and then gains enough energy to become ionized
3
16) The diagram shows a planet at four positions in its orbit. At which position does it have the greatest gravitational potential energy? 3 1 4 2 The gravitational potential energy is the same at all four positions
The total orbital energy is the same at all four positions
17) The diagram shows a planet at four positions in its orbit. At which position does it have the greatest total orbital energy? (Orbital energy is the sum of the planet's kinetic and gravitational potential energy.) 3 1 4 2 The total orbital energy is the same at all four positions
Kinetic energy is the energy an object has due to its motion. A car driving down the highway or molecules of hot, raising up air have kinetic energy.
18) Choose the correct definition and two examples of kinetic energy. Kinetic energy is the energy an object has due to its motion. A car driving down the highway or molecules of hot, raising up air have kinetic energy. Kinetic energy is the energy an object has due to its position. A car driving down the highway or molecules of hot, raising up air have kinetic energy. Kinetic energy is the energy an object has due to its motion. A car resting on the top of a hill or molecules of hot, raising up air have kinetic energy. Kinetic energy is the energy an object has due to its position. A car resting on the top of a hill or molecules of hot, raising up air have kinetic energy
Potential energy is energy that is stored. Two examples are mechanical energy in a compressed spring and gravitational energy in a rock on the top of a hill
18) Choose the correct definition and two examples of potential energy. Potential energy is energy that is stored. Two examples are mechanical energy of a car driving down the highway and thermal energy of molecules of hot air. Potential energy is energy of close molecules' interaction. Two examples are chemical energy in a breakfast cereal and mechanical energy in a compressed spring. Potential energy is energy of close molecules' interaction. Two examples are thermal energy of molecules of hot air and mechanical energy of a rock on the top of a hill. Potential energy is energy that is stored. Two examples are mechanical energy in a compressed spring and gravitational energy in a rock on the top of a hill
Electrons can make a transition from one level to another by taking in or emitting a specific amount of energy. If too much or too little energy is offered, the electron cannot make the transition.
19) Under what circumstances can energy level transitions occur? Electrons can make a transition from one level to another by taking in or emitting a specific amount of energy. If too much energy is offered, the electron can make the transition, however if too little energy is offered the transition cannot occur. Electrons can make a transition from one level to another by taking in or emitting a specific amount of energy. If too much or too little energy is offered, the electron cannot make the transition. Electrons can make a transition from one level to another by taking in or emitting a specific amount of energy. If too little energy is offered, the electron can make the transition, however if too much energy is offered the transition cannot occur
We mean that the electrons can have only discrete values of electrical potential energy in atoms.
19) What do we mean when we say that energy levels are quantized in atoms? We mean that the photons can have only continuous values of electrical potential energy in atoms. We mean that the electrons can have only discrete values of electrical potential energy in atoms. We mean that the electrons can have only continuous electrical potential energy in atoms. We mean that the photons can have only discrete values of electrical potential energy in atoms.
The planet's year would be shorter than Earth's. (This is true because the greater mass of the star would mean a stronger force of gravity at any given distance, which in turn would mean a higher orbital velocity.)
20) Imagine another solar system, with a star more massive than the Sun. Suppose a planet with the same mass as Earth orbits at a distance of 1 AU from the star. How would the planet's year (orbital period) compare to Earth's year? The planet's year would be longer than Earth's. The planet's year would be shorter than Earth's. The planet's year would be the same as Earth's. An orbit at a distance of 1 AU would not be possible around a star more massive than the Sun
electrons escape from atoms.
20) Ionization is the process by which molecules break apart into individual atoms. electrons escape from atoms. liquid materials enters the gas phase
(e) Both (a) and (c)
20) Which of these is happening as a result of the interaction of the Earth's tidal bulge with the Moon? (a) The length of a day on Earth is increasing. (b) The length of a day on Earth is decreasing. (c) The Moon is getting farther from the Earth. (d) The Moon is getting closer to the Earth. (e) Both (a) and (c) (f) Both (b) and (d)
natural consequences of the law of universal gravitation (Kepler discovered his laws by looking for a mathematical way to explain Tycho's observations of the planets. His laws successfully predicted planetary positions, but he did not know why they were true. Newton showed that they are true as a result of the universal law of gravitation)
21) Newton showed that Kepler's laws are _________. the key to proving that Earth orbits our Sun natural consequences of the law of universal gravitation seriously in error actually only three of seven distinct laws of planetary motion
(a) atomic mass number
21) When an atom undergoes radioactive decay, a neutron can turn into a proton (and other particles which we don't need to consider). If the atom retains its original number of electrons, which of these following properties of the atom do not change? (a) atomic mass number (b) atomic number (c) total electric charge (d) Both (a) and (c) (e) Both (b) and (c) (f) (a), (b), and (c)
Earth is 150 million km from the Sun and orbits the Sun in one year. (A single planet's orbital distance and orbital period are all we need to determine the Sun's mass Newton's version of Kepler's third law)
22) Each of the following lists two facts. Which pair of facts can be used with Newton's version of Kepler's third law to determine the mass of the Sun? Earth is 150 million km from the Sun and orbits the Sun in one year. Mercury is 0.387 AU from the Sun and Earth is 1 AU from the Sun. Earth rotates in one day and orbits the Sun in one year. The mass of Earth is 6x10^24 kg and Earth orbits the Sun in one year
This statement makes sense. The redshift means that we see the galaxy moving away from us, so observers in that galaxy must also see us moving away from them—which means they see us redshifted as well.
41) If a distant galaxy has a substantial redshift (as viewed from our galaxy), then anyone living in that galaxy would see a substantial redshift in a spectrum of the Milky Way Galaxy. This statement doesn't make sense. The redshift means that we see the galaxy moving to us, so observers in that galaxy must see us moving away from them—which means they don't see us redshifted. This statement doesn't make sense. The redshift means that we see the galaxy moving away from us, so observers in that galaxy must see us moving to them—which means they don't see us redshifted. This statement makes sense. The redshift means that we see the galaxy moving away from us, so observers in that galaxy must also see us moving away from them—which means they see us redshifted as well. This statement makes sense. The redshift means that we see the galaxy moving to us, so observers in that galaxy must also see us moving to them—which means they see us redshifted as well.
Conduction from heated food heats the dish.
42) Why do dishes that aren't themselves heated by the microwave oven sometimes still get hot when you heat food on them? (Note: It's not a good idea to put empty dishes in a microwave.) Heated food emits infrared radiation, which heats the dish. Rotation of the dish causes doppler shift of micro waves to wavelengths which dishes can absorb. Conduction from heated food heats the dish. Convection between the heated food and the dish occurs.
Some clay dishes contain some water inside them.
42) Why do some clay dishes get hot in the microwave? Phase change similar to the roasting of the clay during the dish manufacturing occurs in some clay dishes. Some clay dishes contain some water inside them. Microwaves can not go through the clay dishes because of the aluminum compounds in the clay. Some clay dishes has a greater heat capacity than a food.
Microwave ovens are tuned to emit frequencies absorbed by water molecules, not by a plastic dish.
42) Why doesn't a microwave oven make a plastic dish get hot? Microwave ovens are tuned to emit frequencies which are reflected by a plastic dishes and not absorbed by them. Microwave ovens are tuned to emit frequencies absorbed by water molecules, not by a plastic dish. Plastic dish has less heat capacity than a food, so temperature of the dish increases by a very small temperature interval. Phase changes occur in the food and almost all of the energy of microwaves is spent on those processes
The passage of a light wave can cause electrically charged particles to move up and down.
5) Which of the following best describes why we say that light is an electromagnetic wave? The passage of a light wave can cause electrically charged particles to move up and down. Light can be produced only by electric or magnetic appliances. Light is produced only when massive fields of electric and magnetic energy collide with one another. The term electromagnetic wave arose for historical reasons, but we now know that light has nothing to do with either electricity or magnetism
X-rays travel through space faster than radio waves. (All light travels at the same speed, so radio waves and X-rays travel at the same speed)
6) Which of the following statements about x-rays and radio waves is not true? X-rays have higher frequency than radio waves. X-rays travel through space faster than radio waves. X-rays and radio waves are both forms of light, or electromagnetic radiation. X-rays have shorter wavelengths than radio waves.
(a) continuous
A metal wire heated to high temperature will emit what kind of spectrum? (a) continuous (b) emission line (c) absorption line
(d) The temperature would appear lower because the peak wavelength will be redshifted.
A perfect thermal emitter is receding from you at high speed. You observe its electromagnetic radiation through a spectrograph and determine its temperature via Wein's law. Will its temperature appear higher or lower than if you observe the object at rest? (a) It would appear fainter but the apparent temperature would not change. (b) There would be no difference because temperature does not depend on the Doppler shift. (c) The temperature would appear higher because the peak wavelength will be blueshifted. (d) The temperature would appear lower because the peak wavelength will be redshifted. (e) The temperature would appear lower because the peak wavelength will be blueshifted.
(a) Yes; the Earth's atmosphere is transparent and the Sun emits radio waves.
Imagine you were born with sensitive radio antennae instead of eyes (lucky you). Assuming you could get out the door to look at the Sun, is it reasonable to expect that you would see it? (a) Yes; the Earth's atmosphere is transparent and the Sun emits radio waves. (b) No; the Sun is a black-body emitter and only emits in the optical. (c) No; the Sun is a black-body emitter and only emits in the optical, UV, and near-IR. (d) No; the atmosphere is opaque at radio wavelengths. (e) Yes; the Earth's atmosphere converts radio waves into optical.
(d) most stars should have planets around them and thus planets are very common in the universe.
One implication of the solar nebular theory is that (a) few stars should have planets around them and thus planets are very uncommon in the universe. (b) our solar system is the only one that contains planets. (c) most stars have collided with other stars to form their planets. (d) most stars should have planets around them and thus planets are very common in the universe. (e) None of these
(e) In the optical, UV, X-ray, or gamma ray region, depending on the temperature change
The sun's surface temperature is around 6,000 K. If it were to suddenly become hotter, where would most of its radiation be emitted? (a) In the optical, infrared, microwave or radio region, depending on the temperature change (b) Uniformly at all wavelengths (c) In the infrared where it is hottest (d) In the optical (e) In the optical, UV, X-ray, or gamma ray region, depending on the temperature change
(a) interferometry
The use of more than one telescope connected together and operating as one instrument in order to achieve higher angular resolution is called ___. (a) interferometry (b) infraredometry (c) interferonetry (d) intraferometry
radiation with a spectrum whose shape depends only on the temperature of the emitting object (It's called thermal radiation because it depends on temperature)
Thermal radiation is defined as __________ radiation that is felt as heat radiation in the form of emission lines from an object radiation produced by an extremely hot object radiation with a spectrum whose shape depends only on the temperature of the emitting object
(e) Gamma rays carry more energy per photon than radio waves.
Why are gamma rays generally harmful to life forms but radio waves generally harmless? (a) Radio waves have a bluer color than gamma rays do. (b) Because radio waves cannot pass through mountains. (c) Gamma rays carry less energy per photon than radio waves. (d) Because gamma rays cannot pass through mountains. (e) Gamma rays carry more energy per photon than radio waves.
(d) clockwise when viewed from above the ecliptic plane.
Venus rotates (a) counterclockwise when viewed from above the ecliptic plane. (b) on its side. (c) in the same direction as all the other planets. (d) clockwise when viewed from above the ecliptic plane. (e) just like Uranus
(c) visible and radio
What kinds of electromagnetic radiation easily penetrate the earth's atmosphere? (a) X-rays and UV radiation (b) radio and infrared (c) visible and radio (d) visible and gamma rays (e) visible and infrared
