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polar molecules tend to have lower boiling points than nonpolar molecules. | (A) true (B) false | B | Changes of state from solid to liquid and from liquid to gas occur when matter gains energy. The energy allows individual molecules to separate and move apart from one another. It takes more energy to bring about these changes of state for polar molecules. Although hydrogen bonds are weak, they add to the energy needed... |
which of the following compounds has the highest melting point? | (A) methane (B) ethylene (C) ammonia (D) water | D | The temperature at which a substance melts is called its melting point. Melting point is a physical property of matter. The gold pictured in the Figure 1.1, for example, has a melting point of 1064 C. This is a high melting point, and most other metals also have high melting points. The melting point of ice, in compari... |
an inclined plane is one of six types of simple machines. | (A) true (B) false | A | An inclined plane is a simple machine that consists of a sloping surface connecting a lower elevation to a higher elevation. An inclined plane is one of six types of simple machines, and it is one of the oldest and most basic. In fact, two other simple machines, the wedge and the screw, are variations of the inclined p... |
simple machines that are variations of the inclined plane include the | (A) screw (B) lever (C) wedge (D) two of the above | D | Two simple machines that are based on the inclined plane are the wedge and the screw. Both increase the force used to move an object because the input force is applied over a greater distance than the output force. |
examples of inclined planes include | (A) ramps (B) playground slides (C) ladders (D) all of the above | D | An inclined plane is a simple machine that consists of a sloping surface connecting a lower elevation to a higher elevation. An inclined plane is one of six types of simple machines, and it is one of the oldest and most basic. In fact, two other simple machines, the wedge and the screw, are variations of the inclined p... |
mechanical advantage is the ratio of input force to output force. | (A) true (B) false | B | How much a machine changes the input force is its mechanical advantage. Mechanical advantage is the ratio of the output force to the input force, so it can be represented by the equation: Actual Mechanical Advantage = Output force Input force Note that this equation represents the actual mechanical advantage of a machi... |
the mechanical advantage of an inclined plane is always | (A) less than 1 (B) equal to 1 (C) greater than 1 (D) equal to zero | C | The mechanical advantage of a simple machine is the factor by which it multiplies the force applied to the machine. It is the ratio of output force (the force put out by the machined) to input force (the force put into the machine). For an inclined plane, less force is put into moving an object up the slope than if the... |
the more gradual the slope of an inclined plane, the greater its mechanical advantage is. | (A) true (B) false | A | The mechanical advantage of a simple machine is the factor by which it multiplies the force applied to the machine. It is the ratio of output force (the force put out by the machined) to input force (the force put into the machine). For an inclined plane, less force is put into moving an object up the slope than if the... |
only moving objects have inertia. | (A) true (B) false | B | The inertia of an object depends on its mass. Objects with greater mass also have greater inertia. Think how hard it would be to push a big box full of books, like the one in Figure 14.3. Then think how easy it would be to push the box if it was empty. The full box is harder to move because it has greater mass and ther... |
newtons first law of motion is also called the law of inertia. | (A) true (B) false | A | Newtons first law of motion is also called the law of inertia. Inertia is the tendency of an object to resist a change in its motion. If an object is already at rest, inertia will keep it at rest. If the object is already moving, inertia will keep it moving. Think about what happens when you are riding in a car that st... |
which object has the greatest inertia? | (A) 5-kg rock (B) 6-kg box of feathers (C) 7-kg bag of groceries (D) 8-kg bowling ball | D | The inertia of an object depends on its mass. Objects with greater mass also have greater inertia. Think how hard it would be to push a big box full of books, like the one in Figure 14.3. Then think how easy it would be to push the box if it was empty. The full box is harder to move because it has greater mass and ther... |
once an object starts moving, inertia keeps it moving without any additional force being applied to the object. | (A) true (B) false | A | Inertia is the tendency of an object to resist a change in its motion. All objects have inertia, whether they are stationary or moving. Inertia explains Newtons first law of motion, which states that an object at rest will remain at rest and an object in motion will stay in motion unless it is acted on by an unbalanced... |
intensity is a measure of a sound waves | (A) speed (B) frequency (C) wavelength (D) energy | D | Loudness refers to how loud or soft a sound seems to a listener. The loudness of sound is determined, in turn, by the intensity of the sound waves. Intensity is a measure of the amount of energy in sound waves. The unit of intensity is the decibel (dB). |
an 80-decibel sound is 20 times louder than a 60-decibel sound. | (A) true (B) false | B | The Figure 1.1 shows decibel levels of several different sounds. As decibel levels get higher, sound waves have greater intensity and sounds are louder. For every 10-decibel increase in the intensity of sound, loudness is 10 times greater. Therefore, a 30-decibel quiet room is 10 times louder than a 20-decibel whisper,... |
the intensity of sound depends on the | (A) amplitude of the sound waves produced by the sound source (B) distance the sound waves have traveled from the sound source (C) speed at which the sound waves traveled from the sound source (D) two of the above | D | Loudness refers to how loud or soft a sound seems to a listener. The loudness of sound is determined, in turn, by the intensity of the sound waves. Intensity is a measure of the amount of energy in sound waves. The unit of intensity is the decibel (dB). |
as distance from the sound source increases, the area covered by the sound waves decreases. | (A) true (B) false | B | The intensity of sound waves determines the loudness of sounds, but what determines intensity? Intensity results from two factors: the amplitude of the sound waves and how far they have traveled from the source of the sound. Amplitude is a measure of the size of sound waves. It depends on the amount of energy that star... |
amplitude is a measure of the size of sound waves. | (A) true (B) false | A | The intensity of sound waves determines the loudness of sounds, but what determines intensity? Intensity results from two factors: the amplitude of the sound waves and how far they have traveled from the source of the sound. Amplitude is a measure of the size of sound waves. It depends on the amount of energy that star... |
which sound is considered to be extremely loud? | (A) dishwasher (B) lawn mower (C) vacuum cleaner (D) two of the above | B | The Figure 1.1 shows decibel levels of several different sounds. As decibel levels get higher, sound waves have greater intensity and sounds are louder. For every 10-decibel increase in the intensity of sound, loudness is 10 times greater. Therefore, a 30-decibel quiet room is 10 times louder than a 20-decibel whisper,... |
all combustion engines | (A) burn fuel to produce thermal energy (B) change thermal energy to kinetic energy (C) burn fuel inside the engine (D) two of the above | D | A combustion engine is a complex machine that burns fuel to produce thermal energy and then uses the energy to do work. Two basic types of combustion engines are external and internal combustion engines. |
in an internal combustion engine, fuel is burned in the | (A) cylinders (B) valves (C) spark plugs (D) pistons | A | An internal combustion engine burns fuel internally, or inside the engine. This type of engine is found not only in cars but in most other motor vehicles as well. The engine works in a series of steps, which keep repeating. You can follow the steps in the Figure 1.1. 1. A mixture of fuel and air is pulled-into a cylind... |
a car engine provides the kinetic energy needed to | (A) turn the wheels (B) apply the brakes (C) power the lights (D) two of the above | A | A combustion engine is a complex machine that burns fuel to produce thermal energy and then uses the energy to do work. In a car, the engine does the work of providing kinetic energy that turns the wheels. The combustion engine in a car is a type of engine called an internal combustion engine. (Another type of combusti... |
all cars have at least eight cylinders. | (A) true (B) false | B | Most cars have at least four cylinders connected to the crankshaft. Their pistons move up and down in sequence, one after the other. A powerful car may have eight pistons, and some race cars may have even more. The more cylinders a car engine has, the more powerful its engine can be. |
the more pistons a car has, the greater the cars power is. | (A) true (B) false | A | Most cars have at least four cylinders connected to the crankshaft. Their pistons move up and down in sequence, one after the other. A powerful car may have eight pistons, and some race cars may have even more. The more cylinders a car engine has, the more powerful its engine can be. |
what is the basic unit of mass in the international system of units? | (A) ounce (B) pound (C) gram (D) kilogram | C | The example of the Mars Climate Orbiter shows the importance of using a standard system of measurement in science and technology. The measurement system used by most scientists and engineers is the International System of Units, or SI. There are a total of seven basic SI units, including units for length (meter) and ma... |
the prefix that multiplies a basic si unit by 0.01 is | (A) kilo- (B) deci- (C) centi- (D) milli- | C | The example of the Mars Climate Orbiter shows the importance of using a standard system of measurement in science and technology. The measurement system used by most scientists and engineers is the International System of Units, or SI. There are a total of seven basic SI units, including units for length (meter) and ma... |
a kilogram equals one-thousandth of a gram. | (A) true (B) false | B | Mass refers to the amount of matter. Mass is usually measured with a balance. A balance allows an object to be matched with other objects of known mass. The SI unit for mass is the kilogram. For smaller masses, grams are often used instead. You may have a balance in your classroom. The balance may be either a triple-be... |
how do ionic bonds form? | (A) Atoms of metallic elements give up electrons to atoms of nonmetallic elements (B) Atoms of nonmetallic elements give up electrons to atoms of metallic elements (C) Atoms of metallic elements accept electrons from atoms of nonmetallic elements (D) two of the above | A | Ionic bonds form only between metals and nonmetals. Thats because metals want to give up electrons, and nonmetals want to gain electrons. Find sodium (Na) in the Figure 1.2. Sodium is an alkali metal in group 1. Like all group 1 elements, it has just one valence electron. If sodium loses that one electron, it will have... |
in an ionic bond, the metallic ion is always a positive ion. | (A) true (B) false | A | A metallic bond is the force of attraction between a positive metal ion and the valence electrons it shares with other ions of the metal. The positive ions form a lattice-like structure. You can see an example in Figure 7.13. (For an animated version, go to the URL below.) The ions are held together in the lattice by b... |
positive ions are named by adding the suffix ide to the first part of the element name. | (A) true (B) false | B | Like fluoride, other negative ions usually have names ending in -ide. Positive ions, on the other hand, are just given the element name followed by the word ion. For example, when a sodium atom loses an electron, it becomes a positive sodium ion. The charge of an ion is indicated by a plus (+) or minus sign (-), which ... |
ionic bonds form only between metals and nonmetals. | (A) true (B) false | A | Ionic bonds form only between metals and nonmetals. Thats because metals want to give up electrons, and nonmetals want to gain electrons. Find sodium (Na) in the Figure 1.2. Sodium is an alkali metal in group 1. Like all group 1 elements, it has just one valence electron. If sodium loses that one electron, it will have... |
atoms of the element sodium want to give up an electron because sodium atoms | (A) already have seven valence electrons (B) do not need any electrons (C) have just one valence electron (D) form negative metal ions | C | Ionic bonds form only between metals and nonmetals. Metals "want" to give up electrons, and nonmetals "want" to gain electrons. Find sodium (Na) in Figure 7.4. Sodium is an alkali metal in group 1. Like other group 1 elements, it has just one valence electron. If sodium loses that one electron, it will have a full oute... |
metals in group 2 of the periodic table form ionic bonds with nonmetals in group | (A) 15 (B) 16 (C) 17 (D) 18 | B | Ionic bonds form only between metals and nonmetals. Thats because metals want to give up electrons, and nonmetals want to gain electrons. Find sodium (Na) in the Figure 1.2. Sodium is an alkali metal in group 1. Like all group 1 elements, it has just one valence electron. If sodium loses that one electron, it will have... |
ionic compounds form when ions of two different elements share electrons. | (A) true (B) false | B | All compounds form when atoms of different elements share or transfer electrons. Compounds in which electrons are transferred from one atom to another are called ionic compounds. In this type of compound, electrons actually move between the atoms, rather than being shared between them. When atoms give up or accept elec... |
an ionic compound is always neutral in charge. | (A) true (B) false | A | Atoms are neutral in electric charge because they have the same number of electrons as protons. However, atoms may transfer electrons and become charged ions, as illustrated in Figure 23.5. Positively charged ions, or cations, form when atoms give up electrons. Negatively charged ions, or anions, form when atoms gain e... |
how are ionic compounds named? | (A) The positive ion comes first in the compound name (B) The negative ion comes first in the compound name (C) The ion in the higher-numbered period comes first in the compound name (D) two of the above | A | Ionic compounds are named for their positive and negative ions. The name of the positive ion always comes first, followed by the name of the negative ion. For example, positive sodium ions and negative chloride ions form the compound named sodium chloride. Similarly, positive calcium ions and negative chloride ions for... |
properties of ionic compounds include | (A) high melting point (B) ability to conduct electricity (C) brittleness (D) two of the above | D | The crystal structure of ionic compounds is strong and rigid. It takes a lot of energy to break all those strong ionic bonds. As a result, ionic compounds are solids with high melting and boiling points (see Table 7.2). The rigid crystals are brittle and more likely to break than bend when struck. As a result, ionic cr... |
uses of ionic compounds include | (A) making fireworks (B) detecting moisture (C) melting ice (D) all of the above | D | Ionic compounds have many uses. Some are shown in the Figure 1.2. Many ionic compounds are used in industry. The human body needs several ions for good health. Having low levels of the ions can endanger important functions such as heartbeat. Solutions of ionic compounds can be used to restore the ions. |
an iodine atom has 53 protons. how many electrons does an iodine anion have? | (A) at least 54 (B) 53 or more (C) 53 or less (D) none of the above | A | Atoms cannot only gain extra electrons. They can also lose electrons. In either case, they become ions. Ions are atoms that have a positive or negative charge because they have unequal numbers of protons and electrons. If atoms lose electrons, they become positive ions, or cations. If atoms gain electrons, they become ... |
what is the name of the ion represented by the following symbol? o2- | (A) oxygen ion (B) dioxide (C) oxide (D) none of the above | C | Like fluoride, other negative ions usually have names ending in -ide. Positive ions, on the other hand, are just given the element name followed by the word ion. For example, when a sodium atom loses an electron, it becomes a positive sodium ion. The charge of an ion is indicated by a plus (+) or minus sign (-), which ... |
the process in which ions form is called ionization. | (A) true (B) false | A | The process in which an atom becomes an ion is called ionization. It may occur when atoms are exposed to high levels of radiation. The radiation may give their outer electrons enough energy to escape from the attraction of the positive nucleus. However, most ions form when atoms transfer electrons to or from other atom... |
ways in which ions may form include | (A) exposure to radiation (B) transfer of electrons between atoms (C) sharing of electrons between atoms (D) two of the above | D | The process in which an atom becomes an ion is called ionization. It may occur when atoms are exposed to high levels of radiation. The radiation may give their outer electrons enough energy to escape from the attraction of the positive nucleus. However, most ions form when atoms transfer electrons to or from other atom... |
ions are very unreactive. | (A) true (B) false | B | Ions are highly reactive, especially as gases. They usually react with ions of opposite charge to form neutral compounds. For example, positive sodium ions and negative chloride ions react to form the neutral compound sodium chloride, commonly known as table salt. This occurs because oppositely charged ions attract eac... |
ions are deflected by a magnetic field. | (A) true (B) false | A | Like the electric field that surrounds a charged particle, a magnetic field surrounds a magnet. This is the area around the magnet where it exerts magnetic force. Figure 24.3 shows the magnetic field surrounding a bar magnet. Tiny bits of iron, called iron filings, were placed under a sheet of glass. When the magnet wa... |
only unsaturated hydrocarbons have isomers. | (A) true (B) false | B | Unsaturated hydrocarbons contain at least one double or triple bond between carbon atoms. As a result, the carbon atoms are unable to bond with as many hydrogen atoms as they would if they were joined only by single bonds. This makes them unsaturated with hydrogen. Unsaturated hydrocarbons are classified on the basis o... |
which statement about the isomers of a given hydrocarbon is true? | (A) They have the same chemical formula (B) They have the same structural formula (C) They have the same number of carbon atoms (D) two of the above | D | Butane has only two isomers and pentane has just three, but some hydrocarbons have many more isomers than these. As you increase the number of carbon atoms in a hydrocarbon, the number of isomers quickly increases. For example, heptane, with seven carbon atoms, has nine isomers; and dodecane, with twelve carbon atoms, ... |
how many isomers does pentane have? | (A) 1 (B) 2 (C) 3 (D) 4 | C | Butane has only two isomers and pentane has just three, but some hydrocarbons have many more isomers than these. As you increase the number of carbon atoms in a hydrocarbon, the number of isomers quickly increases. For example, heptane, with seven carbon atoms, has nine isomers; and dodecane, with twelve carbon atoms, ... |
some hydrocarbons have billions of isomers. | (A) true (B) false | A | Butane has only two isomers and pentane has just three, but some hydrocarbons have many more isomers than these. As you increase the number of carbon atoms in a hydrocarbon, the number of isomers quickly increases. For example, heptane, with seven carbon atoms, has nine isomers; and dodecane, with twelve carbon atoms, ... |
the more branching an isomer has, the lower its melting point is. | (A) true (B) false | A | Because isomers are different compounds, they have different properties. Generally, branched-chain isomers have lower boiling and melting points than straight-chain isomers. For example, the boiling and melting points of iso- butane are -12 C and -160 C, respectively, compared with 0 C and -138 C for n-butane. The ... |
all isotopes form naturally. | (A) true (B) false | B | In elements with more than 83 protons, all of the isotopes are radioactive. In the Figure 1.1, these are the elements with a yellow background. The force of repulsion among all those protons makes the nuclei unstable. Elements with more than 92 protons have such unstable nuclei that they dont even exist in nature. They... |
all isotopes are radioactive. | (A) true (B) false | B | In elements with more than 83 protons, all of the isotopes are radioactive. In the Figure 1.1, these are the elements with a yellow background. The force of repulsion among all those protons makes the nuclei unstable. Elements with more than 92 protons have such unstable nuclei that they dont even exist in nature. They... |
deuterium is an isotope of | (A) oxygen (B) helium (C) carbon (D) hydrogen | D | Hydrogen is an example of an element that has isotopes. Three isotopes of hydrogen are modeled in the Figure hydrogen. Some hydrogen atoms have one neutron as well. These atoms are the isotope named deuterium. Other hydrogen atoms have two neutrons. These atoms are the isotope named tritium. Q: The mass number of an at... |
how many neutrons does the isotope in question 6 have? | (A) one (B) two (C) three (D) four | A | For most other elements, isotopes are named for their mass number. For example, carbon atoms with the usual 6 neutrons have a mass number of 12 (6 protons + 6 neutrons = 12), so they are called carbon-12. Carbon atoms with 7 neutrons have an atomic mass of 13 (6 protons + 7 neutrons = 13). These atoms are the isotope c... |
things with kinetic energy can do work. | (A) true (B) false | A | Kinetic energy is the energy of moving matter. Anything that is moving has kinetic energyfrom atoms in matter to stars in outer space. Things with kinetic energy can do work. For example, the spinning saw blade in the photo above is doing the work of cutting through a piece of metal. |
an objects mass has a greater influence on its kinetic energy than does its velocity. | (A) true (B) false | B | The amount of kinetic energy in a moving object depends directly on its mass and velocity. An object with greater mass or greater velocity has more kinetic energy. You can calculate the kinetic energy of a moving object with this equation: Kinetic Energy (KE) = 12 mass velocity2 This equation shows that an increase in... |
how much kinetic energy does a 50-kg object have if it is moving at a velocity of 2 m/s? | (A) 200 J (B) 100 J (C) 50 J (D) none of the above | B | The amount of kinetic energy in a moving object depends directly on its mass and velocity. An object with greater mass or greater velocity has more kinetic energy. You can calculate the kinetic energy of a moving object with this equation: Kinetic Energy (KE) = 12 mass velocity2 This equation shows that an increase in... |
if the object in question 6 slows down to a velocity of 1 m/s, how much kinetic energy does it have? | (A) 100 J (B) 50 J (C) 25 J (D) none of the above | C | The amount of kinetic energy in a moving object depends directly on its mass and velocity. An object with greater mass or greater velocity has more kinetic energy. You can calculate the kinetic energy of a moving object with this equation: Kinetic Energy (KE) = 12 mass velocity2 This equation shows that an increase in... |
energy can be measured in the si unit n m. | (A) true (B) false | A | Because energy is the ability to do work, it is expressed in the same unit that is used for work. The SI unit for both work and energy is the joule (J), or Newton meter (N m). One joule is the amount of energy needed to apply a force of 1 Newton over a distance of 1 meter. For example, suppose the boy in the Figure 1... |
if particles of matter do not have enough kinetic energy to slide past one another, then the matter exists as a | (A) gas (B) solid (C) liquid (D) plasma | B | Particles of matter of the same substance, such as the same element, are attracted to one another. The force of attraction tends to pull the particles closer together. The particles need a lot of kinetic energy to overcome the force of attraction and move apart. Its like a tug of war between opposing forces. The kineti... |
the particles of solids do not have enough energy to move. | (A) true (B) false | B | Particles of matter of the same substance, such as the same element, are attracted to one another. The force of attraction tends to pull the particles closer together. The particles need a lot of kinetic energy to overcome the force of attraction and move apart. Its like a tug of war between opposing forces. The kineti... |
as the kinetic energy of particles of matter increases, the distance between the particles | (A) vibrates (B) increases (C) decreases (D) remains constant | B | Particles of matter of the same substance, such as the same element, are attracted to one another. The force of attraction tends to pull the particles closer together. The particles need a lot of kinetic energy to overcome the force of attraction and move apart. Its like a tug of war between opposing forces. The kineti... |
scientists think that the particles of all matter are in constant motion. | (A) true (B) false | A | The particles that make up matter are also constantly moving. They have kinetic energy. The theory that all matter consists of constantly moving particles is called the kinetic theory of matter. You can learn more about it at the URL below. |
particles of liquids have enough energy to separate from other liquid particles. | (A) true (B) false | B | Particles of matter of the same substance, such as the same element, are attracted to one another. The force of attraction tends to pull the particles closer together. The particles need a lot of kinetic energy to overcome the force of attraction and move apart. Its like a tug of war between opposing forces. The kineti... |
whenever an action and reaction occur, momentum is | (A) created (B) destroyed (C) transferred (D) none of the above | C | When skater 2 runs into skater 1, hes going faster than skater 1 so he has more momentum. Momentum is a property of a moving object that makes it hard to stop. Its a product of the objects mass and velocity. At the moment of the collision, skater 2 transfers some of his momentum to skater 1, who shoots forward when ska... |
when momentum is transferred from one object to another, their combined momentum remains the same. | (A) true (B) false | A | When an action and reaction occur, momentum is transferred from one object to the other. However, the com- bined momentum of the objects remains the same. In other words, momentum is conserved. This is the law of conservation of momentum. Consider the example of a truck colliding with a car, which is illustrated in Fig... |
when light reflects off a smooth surface, it forms a clear image. | (A) true (B) false | A | Reflection of light occurs when light bounces back from a surface that it cannot pass through. Reflection may be regular or diffuse. If the surface is very smooth, like a mirror, the reflected light forms a very clear image. This is called regular, or specular, reflection. In the Figure 1.1, the smooth surface of the s... |
the type of reflection described in question 3 is called | (A) normal reflection (B) diffuse reflection (C) regular reflection (D) none of the above | C | If a surface is extremely smooth, as it is in a mirror, then the image formed by reflection is sharp and clear. This is called regular reflection (also called specular reflection). However, if the surface is even slightly rough or bumpy, an image may not form, or if there is an image, it is blurry or fuzzy. This is cal... |
rays of light are reflected in many different directions in | (A) specular reflection (B) regular reflection (C) diffuse reflection (D) all of the above | C | Almost all surfaces reflect some of the light that strikes them. The still water of the lake in Figure 22.9 reflects almost all of the light that strikes it. The reflected light forms an image of nearby objects. An image is a copy of an object that is formed by reflected or refracted light. |
the image formed when light rays are reflected as described in question 5 is blurry or fuzzy. | (A) true (B) false | A | If a surface is extremely smooth, as it is in a mirror, then the image formed by reflection is sharp and clear. This is called regular reflection (also called specular reflection). However, if the surface is even slightly rough or bumpy, an image may not form, or if there is an image, it is blurry or fuzzy. This is cal... |
the angles of reflection and incidence are measured relative to a line that is parallel to the reflective surface. | (A) true (B) false | B | One thing is true of both regular and diffuse reflection. The angle at which the reflected rays leave the surface is equal to the angle at which the incident rays strike the surface. This is known as the law of reflection. The law is illustrated in the Figure 1.3. |
a lens reflects light and forms an image. | (A) true (B) false | B | A lens is a transparent object with one or two curved surfaces. It is typically made of glass (or clear plastic in the case of a contact lens). A lens refracts, or bends, light and forms an image. An image is a copy of an objected formed by the refraction (or reflection) of visible light. The more curved the surface of... |
the less curved the surface of a lens is, the more the lens refracts light. | (A) true (B) false | B | Lenses make use of the refraction of light to create images. A lens is a transparent object, typically made of glass, with one or two curved surfaces. The more curved the surface of a lens is, the more it refracts light. Like mirrors, lenses may be concave or convex. |
the image of an object formed by a concave lens is always | (A) on the same side of the lens as the object (B) smaller than the object (C) right-side up (D) all of the above | D | Concave lenses are thicker at the edges than in the middle. They cause rays of light to diverge, or spread apart. Figure 22.16 shows how a concave lens forms an image. The image is always virtual and on the same side of the lens as the object. The image is also right-side up and smaller than the object. Concave lenses ... |
a concave lens forms only real images. | (A) true (B) false | B | Concave lenses are thicker at the edges than in the middle. They cause rays of light to diverge, or spread apart. Figure 22.16 shows how a concave lens forms an image. The image is always virtual and on the same side of the lens as the object. The image is also right-side up and smaller than the object. Concave lenses ... |
a convex lens forms a virtual image when the object is | (A) closer to the lens than the focus is (B) farther from the lens than the focus is (C) the same distance from the lens as the focus is (D) on the opposite side of the lens from the focus | A | A concave lens is thicker at the edges than it is in the middle. You can see the shape of a concave lens in the Figure Note that the image formed by a concave lens is on the same side of the lens as the object. It is also smaller than the object and right-side up. However, it isnt a real image. It is a virtual image. Y... |
levers that change the direction of the force are | (A) first class levers (B) second class levers (C) third class levers (D) all of the above | A | Some machines change the direction of the force applied by the user. They may or may not also change the strength of the force or the distance over which it is applied. Two examples of machines that work in this way are claw hammers and the rope systems (pulleys) that raise or lower flags on flagpoles. Figure 16.10 exp... |
examples of first-class levers include | (A) see saws (B) wheelbarrows (C) rakes (D) two of the above | A | Did you ever use a hammer to pull a nail out of a board? If not, you can see how its done in Figure 16.18. When you pull down on the handle of the hammer, the claw end pulls up on the nail. A hammer is an example of a lever. A lever is a simple machine consisting of a bar that rotates around a fixed point called the fu... |
all of the following are third-class levers except | (A) brooms (B) hockey sticks (C) rakes (D) wheelbarrows | D | You may be wondering why you would use a third-class lever when it doesnt change the direction or strength of the applied force. The advantage of a third-class lever is that the output force is applied over a greater distance than the input force. This means that the output end of the lever must move faster than the in... |
a second class lever always has an ideal mechanical advantage less than 1. | (A) true (B) false | B | All three classes of levers make work easier, but they do so in different ways. When the input and output forces are on opposite sides of the fulcrum, the lever changes the direction of the applied force. This occurs only with a first-class lever. When both the input and output forces are on the same side of the fulcru... |
a third class lever always applies the output force over a greater distance than the input force. | (A) true (B) false | A | You may be wondering why you would use a third-class lever when it doesnt change the direction or strength of the applied force. The advantage of a third-class lever is that the output force is applied over a greater distance than the input force. This means that the output end of the lever must move faster than the in... |
sunlight carries the complete range of wavelengths of electromagnetic waves. | (A) true (B) false | A | Electromagnetic waves are waves that carry energy through matter or space as vibrating electric and magnetic fields. Electromagnetic waves have a wide range of wavelengths and frequencies. Sunlight contains the complete range of wavelengths of electromagnetic waves, which is called the electromagnetic spectrum. The Fig... |
light includes | (A) visible light (B) ultraviolet light (C) infrared light (D) all of the above | D | The Suns surface features are quite visible, but only with special equipment. For example, sunspots are only visible with special light-filtering lenses. |
sources of infrared light include | (A) the sun (B) flames (C) living things (D) all of the above | D | Light with the longest wavelengths is called infrared light. The term infrared means "below red." Infrared light is the range of light waves that have longer wavelengths than red light in the visible spectrum. You cant see infrared light waves, but you can feel them as heat on your skin. The sun gives off infrared ligh... |
visible light with the highest frequencies appears to our eyes as the color | (A) red (B) yellow (C) green (D) violet | D | Visible light is light that has wavelengths that can be detected by the human eye. The wavelength of visible light determines the color that the light appears. As you can see in the Figure 1.1, light with the longest wavelength appears red, and light with the shortest wavelength appears violet. In between are all the o... |
ultraviolet light can be used to kill bacteria in food. | (A) true (B) false | A | Bacteria in food or water usually can be killed by heating it to a high temperature. Generally, this temperature is at least 71 C (160 F). Bacteria on surfaces such as countertops and floors can be killed with disinfectants, such as chlorine bleach. Bacterial infections in people can be treated with antibiotic drugs. T... |
lipids are biochemical compounds that include fats and oils. | (A) true (B) false | A | Lipids are biochemical compounds such as fats and oils. Organisms use lipids to store energy. In addition to carbon and hydrogen, lipids contain oxygen. |
all lipids contain | (A) oxygen (B) nitrogen (C) phosphorus (D) two of the above | A | Lipids are biochemical compounds such as fats and oils. Organisms use lipids to store energy. In addition to carbon and hydrogen, lipids contain oxygen. |
lipids known as fats consist of saturated fatty acids. | (A) true (B) false | A | Lipids are made up of long carbon chains called fatty acids. Like hydrocarbons, fatty acids may be saturated or unsaturated. Figure 9.21 shows structural formulas for two small fatty acids. One is saturated and one is unsaturated. In saturated fatty acids, there are only single bonds between carbon atoms. As a result, ... |
unsaturated fatty acids contain only single bonds between carbon atoms. | (A) true (B) false | B | Lipids consist only or mainly of carbon, hydrogen, and oxygen. Both fats and oils are made up of long chains of carbon atoms that are bonded together. These chains are called fatty acids. Fatty acids may be saturated or (A) The white bands on these lamb chops are fat. (B) The yellow liquid in this bottle is olive oil. ... |
a longitudinal wave is a type of mechanical wave. | (A) true (B) false | A | A longitudinal wave is a type of mechanical wave. A mechanical wave is a wave that travels through matter, called the medium. In a longitudinal wave, particles of the medium vibrate in a direction that is parallel to the direction that the wave travels. You can see this in the Figure 1.1. The persons hand pushes and pu... |
in a longitudinal wave, particles of the medium vibrate in a direction that is perpendicular to the direction the wave travels. | (A) true (B) false | B | A longitudinal wave is a type of mechanical wave. A mechanical wave is a wave that travels through matter, called the medium. In a longitudinal wave, particles of the medium vibrate in a direction that is parallel to the direction that the wave travels. You can see this in the Figure 1.1. The persons hand pushes and pu... |
earthquakes cause longitudinal waves called p waves. | (A) true (B) false | A | Earthquakes cause longitudinal waves as well as transverse waves. The disturbance that causes an earthquake sends longitudinal waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called primary, or P, waves. They are illustrated in Figure 19.7. |
a longitudinal wave that carries more energy has particles that are | (A) closer together in rarefactions (B) father apart in compressions (C) the same distance apart everywhere (D) none of the above | D | A longitudinal wave is a type of mechanical wave. A mechanical wave is a wave that travels through matter, called the medium. In a longitudinal wave, particles of the medium vibrate in a direction that is parallel to the direction that the wave travels. You can see this in the Figure 1.1. The persons hand pushes and pu... |
earths magnetic poles have switched places repeatedly in the past. | (A) true (B) false | A | Earths magnetic poles have switched places repeatedly in the past. As you can see in the Figure 1.1, each time the switch occurred, Earths magnetic field was reversed. The magnetic field is the region around a magnet over which it exerts magnetic force. We think of todays magnetic field direction as normal, but thats o... |
scientists know for certain why magnetic field reversals occur. | (A) true (B) false | B | Scientists dont know for certain why magnetic reversals occur, but there is hard evidence that they have for hundreds of millions of years. The evidence comes from rocks on the ocean floor. Look at Figure 1.2. They show the same ridge on the ocean floor during different periods of time. A. At the center of the ridge, h... |
evidence for magnetic field reversals | (A) covers 100s of millions of years (B) was discovered on the ocean floor (C) comes from the magnetic domains of rocks (D) all of the above | D | Scientists dont know for certain why magnetic reversals occur, but there is hard evidence that they have for hundreds of millions of years. The evidence comes from rocks on the ocean floor. Look at Figure 1.2. They show the same ridge on the ocean floor during different periods of time. A. At the center of the ridge, h... |
when did the last magnetic reversal occur? | (A) more than 330 million years ago (B) about 300 million years ago (C) about 100 million years ago (D) less than 1 million years ago | D | Do you like to read science fiction? Science fiction writers are really creative. For example, an author might write about a time in the distant past when compasses pointed south instead of north. Actually, this idea isnt fictionits a fact! Earths magnetic poles have switched places repeatedly over the past hundreds of... |
rocks on the ocean floor far from a ridge | (A) are older than rocks close to the ridge (B) always have reversed polarity (C) keep reversing the polarity of their magnetic domains (D) two of the above | A | The scientists used geologic dating techniques on seafloor rocks. They found that the youngest rocks on the seafloor were at the mid-ocean ridges. The rocks get older with distance from the ridge crest. The scientists were surprised to find that the oldest seafloor is less than 180 million years old. This may seem old,... |
after magma hardens, the alignment of magnetic domains reverses with each magnetic field reversal. | (A) true (B) false | B | Scientists dont know for certain why magnetic reversals occur, but there is hard evidence that they have for hundreds of millions of years. The evidence comes from rocks on the ocean floor. Look at Figure 1.2. They show the same ridge on the ocean floor during different periods of time. A. At the center of the ridge, h... |
only bar magnets have north and south magnetic poles. | (A) true (B) false | B | All magnets have two magnetic poles. The poles are regions where the magnet is strongest. The poles are called north and south because they always line up with Earths north-south axis if the magnet is allowed to move freely. (Earths axis is the imaginary line around which the planet rotates.) What do you suppose would ... |
if you cut a bar magnet in half, one half will have just a north pole and the other half will have just a south pole. | (A) true (B) false | B | All magnets have two magnetic poles. The poles are regions where the magnet is strongest. The poles are called north and south because they always line up with Earths north-south axis if the magnet is allowed to move freely. (Earths axis is the imaginary line around which the planet rotates.) What do you suppose would ... |
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