**Physics Final Practice Test**

A good score is at least 75 correct. Answers are provided at the end. It is best to have a friend check your score the first time so that you won’t memorize the answers if you want to take the test again.

1. A pellet gun shoots a projectile whose mass is 0.125 g at a speed of 100 m/s. Neglecting the effect of gravity, what is the magnitude of the momentum vector of the object as it leaves the gun?

(a) 0.00125 kg · m/s

(b) 0.0125 kg · m/s

(c) 0.125 kg · m/s

(d) 1.25 kg · m/s

(e) 12.5 kg · m/s

2. Suppose that you are on board a spacecraft in a weightless environment. You attach a ball to a string and whirl the ball around your body at a constant angular speed. The acceleration vector of the ball

(a) points in the same direction as the ball is moving at any given instant in time.

(b) always points inward toward you.

(c) always points outward away from you.

(d) is zero because the velocity is not changing.

(e) points in a direction perpendicular to the plane in which the ball revolves.

3. It takes a certain amount of energy to change a sample of solid matter to its liquid state, assuming that the matter is of the sort that can exist in either of these two states. This quantity varies for different substances and is called the

(a) liquefaction energy.

(b) melting energy.

(c) heat of fusion.

(d) thawing energy.

(e) critical point.

4. Unless acted on by an outside force, an object moving with uniform velocity

(a) gradually comes to rest.

(b) abruptly comes to rest.

(c) falls to the Earth.

(d) continues to move at that velocity.

(e) has no momentum.

5. Two-thirds of an ac cycle is the equivalent of

(a) 60 degrees of phase.

(b) 120 degrees of phase.

(c) 180 degrees of phase.

(d) 240 degrees of phase.

(e) 270 degrees of phase.

6. Three inductors, each with a value of 30 µH, are connected in parallel. There is no mutual inductance among them. The net inductance of the parallel-connected set is

(a) 30 µH.

(b) 90 µH.

(c) 10 µH.

(d) dependent on the frequency of the ac passing through it.

(e) impossible to determine.

7. Suppose that a jar is filled with liquid, and then another liquid that does not react chemically with the first liquid is introduced into the jar. Gradually, the two liquids blend together. This process is

(a) dispersion.

(b) diffusion.

(c) a change of state.

(d) fusion.

(e) molecular averaging.

8. In an electrical circuit, the complex number 5 − *j* 7 represents

(a) 5 ohms of reactance and 7 farads of capacitance.

(b) 5 ohms of resistance and 7 ohms of capacitive reactance.

(c) 5 ohms of resistance and 7 ohms of inductive reactance.

(d) 5 ohms of reactance and 7 henrys of inductance.

(e) none of the above.

9. When a semiconductor diode is reverse-biased with a steady dc voltage less than the avalanche voltage,

(a) it conducts well.

(b) it conducts some of the time.

(c) it conducts poorly or not at all.

(d) it has low resistance.

(e) it has high inductance.

10. Protons and neutrons

(a) have nearly the same mass, but protons have electric charge while neutrons do not.

(b) have vastly different masses and equal but opposite electric charges.

(c) have vastly different masses but identical electric charges.

(d) have zero mass, no electric charge, and travel at the speed of light.

(e) annihilate if they collide.

11. Suppose that a certain computer has a clock speed specified in gigahertz. If you wanted to talk about the clock speed in terahertz instead, you would use a number

(a) a thousand times larger.

(b) a million times larger.

(c) a thousand times smaller.

(d) a million times smaller.

(e) the same size.

12. Even if the voltage across a sample is large, the current through it is small if

(a) the ohmic value is low.

(b) the conductance is high.

(c) electrons pass easily from atom to atom.

(d) the material is a conductor such as copper or silver.

(e) the resistance is high.

13. One microwatt is the equivalent of

(a) 10 ^{−6} joule-seconds.

(b) 10 ^{−6} joules per seconds.

(c) 10 ^{−6} ampere-seconds.

(d) 10 ^{−6} ampere per seconds.

(e) 10 ^{−6} ergs per second.

14. If you place a kettle of water on a hot stove, heat is transferred from the burner to the kettle and from the kettle to the water. This is an example of

(a) convection.

(b) conduction.

(c) evaporation.

(d) condensation.

(e) radiation.

15. A specific impedance can be completely defined in terms of

(a) a scalar quantity.

(b) a vector quantity.

(c) a magnetic field.

(d) an electrical field.

(e) a combination of voltage and current.

16. Demodulation is the process of

(a) recovering the data from a signal carrier.

(b) impressing data onto a signal carrier.

(c) conversion of ac to dc.

(d) conversion of dc to ac.

(e) elimination of unwanted fluctuations in a signal.

17. When the relative hardness of two substances is determined according to the Mohs scale, the following rule or rules apply:

(a) A substance always scratches something softer than itself; a substance never scratches anything harder than itself.

(b) A substance cannot scratch anything softer than itself.

(c) Substances scratch each other only when one substance is much harder than the other.

(d) Harder substances are shattered when struck by softer substances.

(e) None of the above are true.

18. Extremely-low-frequency (ELF) radiation is not

(a) produced by computer monitors.

(b) a form of electromagnetic field.

(c) a form of ionizing radiation.

(d) a subject of any interest to scientists or engineers.

(e) produced by fluctuating electrical or magnetic fields.

19. The current path in a field-effect transistor is called the

(a) gate.

(b) channel.

(c) base.

(d) substrate.

(e) collector.

20. The foot-pound-second (fps) system of units

(a) is preferred by scientists in Europe.

(b) is preferred by scientists in the United States.

(c) is used by some lay people.

(d) is also known as the International System.

(e) is based on quantities related by powers of 10.

21. Under what circumstances is the shortest distance between two points a curve rather than a straight line?

(a) Under no circumstances

(b) When space is “flat”

(c) When two observers are moving relative to each other at constant speed

(d) In the presence of a powerful gravitational field

(e) Whenever clocks are not synchronized

22. Which of the statements (a, b, c, d, or e) below is *false?*

(a) The current into any point in a dc electric circuit is the same as the current going out of that point.

(b) In a simple dc circuit, the current is proportional to the voltage divided by the resistance.

(c) If the resistance of a component in a dc circuit remains constant while the voltage across it decreases, the current across it decreases.

(d) If the voltage across a resistor in a dc circuit doubles while the resistance remains constant, the power dissipated in the resistor doubles.

(e) All the statements are true.

23. The emitter in an *npn* bipolar transistor

(a) must always be connected to an electrical ground.

(b) always provides the output signal.

(c) is a thin *p* -type layer sandwiched in between two n-type layers.

(d) consists of *n* -type semiconductor material.

(e) usually acts as the control electrode.

24. When a vector quantity **v** (such as velocity) is divided by a scalar quantity *k* , the result is

(a) a vector whose direction is the same as that of **v** and whose magnitude is 1/ *k* that of **v** .

(b) a scalar equal to **v** / *k* .

(c) a vector whose direction is opposite that of v and whose magnitude is 1/ *k* that of **v** .

(d) a scalar equal to − **v** / *k* .

(e) meaningless; a vector cannot be divided by a scalar.

25. The rate at which time “flows” depends on

(a) absolute position in space.

(b) the intensity of the gravitational field.

(c) the speed of light.

(d) the intensity of the Earth’s magnetic field.

(e) all of the above.

26. Different elements can join together, sharing electrons. When this happens, the result is

(a) an ion.

(b) a compound.

(c) an isotope.

(d) an electrical conductor.

(e) antimatter.

27. Suppose that a gas is placed in a sealed rigid chamber under high pressure. Suddenly, a significant amount of the gas is allowed to escape. What happens?

(a) Inside the chamber, the gas gets cooler.

(b) Inside the chamber, the gas gets warmer.

(c) Inside the chamber, the volume of gas decreases.

(d) Inside the chamber, the gas molecules speed up.

(e) The gas condenses as it leaves the chamber.

28. Full-duplex two-way communication by radio, in which either station operator can interrupt the other in an instant, will be impossible between stations on Earth and any interstellar space vessel

(a) because of relativistic time dilation.

(b) because of the difference in relative velocity of the two stations.

(c) because the speed of EM wave propagation is only 3 × 10 ^{8} m/s.

(d) because of red shift.

(e) No! The premise is wrong; such communication is possible.

29. Which of the following statements is *false?*

(a) A mass can be weightless.

(b) Force is proportional to mass times acceleration.

(c) Every action is attended by an equal and opposite reaction.

(d) Mass is a vector quantity.

(e) Velocity has both magnitude and direction.

30. A sample of liquid has a volume of 1.200 liters. Its mass is 2.400 kilograms. What is its density?

(a) 2.000 kg/m ^{3}

(b) 20.00 kg/m ^{3}

(c) 200.0 kg/m ^{3}

(d) 2,000 kg/m ^{3}

(e) It cannot be determined without more information.

31. The geomagnetic field is produced by

(a) the solar wind.

(b) the aurorae.

(c) the ionosphere.

(d) molten iron circulating inside the Earth.

(e) radioactivity.

32. Which of the following statements is *false?*

(a) Speed is a scalar quantity, but velocity is a vector quantity.

(b) Velocity consists of a speed component and a direction component.

(c) An object can have constant speed but changing velocity.

(d) Speed is the magnitude of a velocity vector.

(e) None of the above; they are all true.

33. Fahrenheit and Celsius readings are the same

(a) at 0° in either scale.

(b) at 4° in either scale.

(c) at 100° in either scale.

(d) at −40° in either scale.

(e) at no point in either scale.

34. Suppose that you connect a lightbulb across a common 6.0-V lantern battery. The bulb lights up (and does not burn out) and draws 1.5 W of power. What is the current through the bulb?

(a) 9.0 A

(b) 4.0 A

(c) 0.38 A

(d) 0.25 A

(e) It cannot be calculated from this information.

35. Inductance is the opposition of an electrical component to ac by temporarily storing some of the electrical energy in the form of

(a) heat.

(b) a magnetic field.

(c) an electrical field.

(d) visible light.

(e) momentum.

36. Avogadro’s number, equal to approximately 6.02 × 10 ^{23} , is a unit of material quantity also known as a

(a) mole.

(b) candela.

(c) metric ton.

(d) gross.

(e) myriad.

37. According to Einstein’s special theory of relativity, the luminiferous ether

(a) passes through matter as easily as it does through space.

(b) affects the speed of light, depending on the location of the observer.

(c) affects the speed of light, depending on the motion of the observer.

(d) is the absolute standard for motion in the universe.

(e) does not necessarily exist at all.

38. A lodestone orients itself in a particular direction because of

(a) interaction between it and the Earth’s magnetic field.

(b) gravitational effects.

(c) tidal effects.

(d) the Earth’s rotation.

(e) the fact that it is irregularly shaped.

39. Capacitances in series add like

(a) inductances in series.

(b) resistances in parallel.

(c) voltages in parallel.

(d) magnetic fields in series.

(e) none of the above.

40. A volume of 1 milliliter (1 ml) is the same as a volume of

(a) 1 mm ^{3} .

(b) 1 cm ^{3} .

(c) 1 mm ^{2} .

(d) 1 cm ^{2} .

(e) none of the above.

41. The objective in a reflecting telescope is

(a) a convex mirror.

(b) a concave mirror.

(c) a convex lens.

(d) a concave lens.

(e) a planoconcave lens.

42. A compound microscope has

(a) a convex objective and a convex eyepiece.

(b) a concave objective and a concave eyepiece.

(c) a concave objective and a convex eyepiece.

(d) a convex objective and a concave eyepiece.

(e) a single compound lens.

43. The sum of all the voltages, as you go around a dc circuit from a fixed point and return there from the opposite direction, and taking polarity into account,

(a) depends on the current.

(b) depends on the number of components.

(c) is zero.

(d) is positive.

(e) is negative.

44. A certain appliance consumes energy at a rate of 1,200 joules per minute. This is the same as saying that the appliance consumes

(a) 20 ergs.

(b) 20 newtons.

(c) 20 meters per second squared.

(d) 20 kilograms per second squared.

(e) 20 watts.

45. A converging lens

(a) brings parallel light rays to a focus.

(b) spreads parallel light rays out.

(c) makes converging light rays parallel.

(d) can do any of a, b, and c.

(e) can do none of a, b, or c.

46. Which of the following is *not* a variable in an electromagnetic wave?

(a) Frequency

(b) Amplitude

(c) Period

(d) Resolution

(e) Wavelength

47. The term *phase opposition* for two sine waves having the same frequency means that they differ in phase by

(a) zero.

(b) π/2 radians.

(c) π radians.

(d) 3π/2 radians.

(e) 2π radians.

48. In every respect, acceleration force manifests itself in precisely the same way as

(a) the force caused by gravitation.

(b) the force caused by time dilation.

(c) the force caused by high speeds.

(d) the force caused by constant relative motion.

(e) none of the above.

49. Diffraction makes it possible for

(a) ocean waves to interact so that they amplify each other’s effects.

(b) sound waves to travel faster than they normally would.

(c) harmonic radio waves to be generated.

(d) monochromatic light to be turned into white light.

(e) sound waves to propagate around corners.

50. An asset of integrated-circuit (IC) technology is the fact that it

(a) allows for miniaturization.

(b) allows for modular construction of circuits, devices, and systems.

(c) consumes less power than equivalent circuits made of discrete components.

(d) optimizes task speed by minimizing the distances among individual active components.

(e) does all of the above.

51. Mechanical work can be defined in terms of

(a) the product of force and mass.

(b) the product of force and speed.

(c) the product of force and acceleration.

(d) the product of force and displacement.

(e) the product of force and energy.

52. In the presence of unusual solar activity, the “northern lights” often reflect radio waves at some frequencies. This is called

(a) a geomagnetic storm.

(b) auroral propagation.

(c) total internal reflection.

(d) sporadic-E propagation.

(e) space-wave propagation.

53. A constant force of 3.00 N is applied to a mass of 6.00 kg in deep space, far away from the gravitational influence of any star or planet. What is the magnitude of the acceleration?

(a) It cannot be determined from this information.

(b) 0.500 m/s ^{2}

(c) 0.667 m/s ^{2}

(d) 1.50 m/s ^{2}

(e) 2.00 m/s ^{2}

54. Square, ramp, sawtooth, and triangular waves

(a) are infinitely high in frequency.

(b) are composites of sinusoids in specific proportions.

(c) have no defined wavelengths.

(d) travel faster than sine waves in the same medium.

(e) all contain energy at a single frequency.

55. The magnetic flux density in a specific spot near a current-carrying wire is

(a) inversely proportional to the current in the wire.

(b) directly proportional to the current in the wire.

(c) inversely proportional to the square of the current in the wire.

(d) directly proportional to the square of the current in the wire.

(e) constant regardless of the current in the wire.

56. The unit of ionizing radiation representing one nuclear transition per second is the

(a) hertz.

(b) meter per second.

(c) becquerel.

(d) ampere.

(e) joule.

57. Two atoms are scrutinized. Their nuclei have the same number of protons, but one nucleus has two neutrons more than the other. These atoms represent

(a) the same element and the same isotope.

(b) different elements but the same isotope.

(c) the same element but different isotopes.

(d) different elements and different isotopes.

(e) an impossible situation; this scenario cannot occur.

58. Fill in the blank in the following sentence to make it *true:* “For any natural source of ionizing radiation, such as radium or uranium, there is a ________that is a function of the radiation intensity versus time.”

(a) wavelength

(b) frequency

(c) period

(d) decay curve

(e) bandwidth

59. Suppose that an ac voltage has a dc voltage superimposed and that the dc voltage exceeds the peak amplitude of the ac voltage. The polarity of the resulting wave

(a) does not change, and its amplitude does not vary.

(b) does not change, although its amplitude varies.

(c) changes at the same frequency as that of the ac wave.

(d) changes at half the frequency as that of the ac wave.

(e) cannot be described without more information.

60. The density of an elemental gas such as helium can be defined in terms of

(a) the number of atoms per unit displacement.

(b) the number of atoms per unit area.

(c) the number of atoms per unit mass.

(d) the number of atoms per unit volume.

(e) the number of atoms per unit weight.

61. A constant such as *e* or π, presented as a plain number without any units associated, is called

(a) a physical constant.

(b) a relative constant.

(c) an absolute constant.

(d) a qualitative constant.

(e) a dimensionless constant.

62. Suppose that a radio wave has a frequency of 60 MHz. What is the wavelength in a vacuum? Consider the propagation speed of an electromagnetic wave in free space to be 3.00 × 10 ^{8} m/s.

(a) 5.0 m

(b) 20 m

(c) 180 m

(d) 1.8 X 10 ^{4} m

(e) It cannot be calculated from this information.

63. Suppose that a length of wire 10.00 m long is hung from a tree during a warm afternoon when the temperature is 35°C. During the predawn hours, the temperature has dropped to 20°C, and the wire measures 9.985 m in length. What is the coefficient of linear expansion of this wire?

(a) It can’t be determined from this information.

(b) 10 ^{−5} /°C

(c) 10 ^{−4} /°C

(d) 0.001/°C

(e) 0.01/°C.

64. Total internal reflection can occur for a light beam

(a) striking a pane of glass from the outside.

(b) passing through a pane of glass at a right angle.

(c) striking the surface of a prism at a grazing angle from the inside.

(d) traveling from one place to another through a vacuum.

(e) under no circumstances.

65. The Earth’s ionosphere can affect

(a) the propagation of light waves.

(b) the conductivity of copper wires.

(c) the intensity of a solar flare.

(d) the propagation of radio waves at certain frequencies.

(e) the apparent magnitudes of distant stars.

66. Impulse is equivalent to

(a) a change in kinetic energy.

(b) a change in potential energy.

(c) a change in momentum.

(d) a change in mass.

(e) a change in speed.

67. Fill in the blank in the following sentence to make it *true:* “If wave *X* begins a small fraction of a cycle earlier than wave *Y* , then wave *X* __________wave *Y* in phase.”

(a) leads

(b) lags

(c) opposes

(d) is in quadrature with

(e) is coincident with

68. Which of the following components can be used to build a voltage amplifier?

(a) an electrochemical cell

(b) an electric generator

(c) a photovoltaic cell

(d) a field-effect transistor

(e) a diode

69. When water is electrolyzed,

(a) the protons are stripped from the atomic nuclei.

(b) hydrogen and oxygen combine.

(c) hydrogen and oxygen atoms are separated from each other.

(d) new isotopes are formed.

(e) nuclear fission occurs.

70. Given an object at a specific and constant temperature, the number representing the Celsius temperature of the object is

(a) approximately 273 greater than the number representing the Kelvin temperature.

(b) approximately 273 less than the number representing the Kelvin temperature.

(c) approximately 460 greater than the number representing the Kelvin temperature.

(d) approximately 460 less than the number representing the Kelvin temperature.

(e) approximately of the number representing the Kelvin temperature.

71. Complex-number impedance is comprised of

(a) resistance, capacitance, and inductance.

(b) reactance, capacitance, and inductance.

(c) capacitive and inductive reactance.

(d) resistance, capacitive reactance, and inductive reactance.

(e) reactance, capacitive resistance, and inductive resistance.

72. Which of the following is a scalar quantity?

(a) Displacement

(b) Velocity

(c) Mass

(d) Acceleration

(e) All of the above

73. In a complete standing-wave cycle, there are

(a) two loops and two nodes.

(b) two loops and one node.

(c) two nodes and one loop.

(d) infinitely many loops and nodes.

(e) no loops or nodes.

74. The term *black light* refers to

(a) radio waves.

(b) infrared radiation.

(c) ultraviolet radiation.

(d) visible light of extremely low intensity.

(e) visible light with no definable wavelength.

75. An important characteristic of a solid is its density relative to that of pure liquid water at 4°C. This is known as

(a) specific density.

(b) specific mass.

(c) specific weight.

(d) specific volume.

(e) specific gravity.

76. The magnitude of the kinetic energy in a moving object is directly proportional to the square of its

(a) mass.

(b) acceleration.

(c) weight.

(d) displacement.

(e) speed.

77. Retentivity is a measure of how well a substance can

(a) reverse its magnetic polarity.

(b) become temporarily magnetized.

(c) become permanently magnetized.

(d) be demagnetized.

(e) concentrate magnetic lines of flux.

78. The prefix *pico-* in front of a unit refers to

(a) 10 ^{−18} of that unit.

(b) 10 ^{−15} of that unit.

(c) 10 ^{−12} of that unit.

(d) 10 ^{12} times that unit.

(e) 10 ^{18} times that unit.

79. In an electromagnetic field, the direction of wave travel is

(a) parallel to the magnetic lines of flux.

(b) parallel to the electrical lines of flux.

(c) parallel to the electrical and the magnetic lines of flux.

(d) parallel to neither the electrical nor the magnetic lines of flux.

(e) dependent on the wavelength.

80. Four resistors are connected in series. Two of them have resistances of 120 Ω, and the other two have resistances of 150 Ω. The total resistance is

(a) 540 Ω

(b) 270 Ω

(c) 133 Ω

(d) 33.3 Ω

(e) It cannot be calculated from this information.

81. A telescope has an objective lens with a diameter of 250 mm. An eyepiece with a focal length of 10 mm is used. What is the magnification?

(a) 25×

(b) 2,500×

(c) 250×

(d) 10×

(e) It cannot be calculated from this information.

82. In a rigid chamber filled with an elemental gas such as oxygen at a constant temperature,

(a) the pressure is proportional to the number of atoms of gas in the chamber.

(b) the pressure is inversely proportional to the number of atoms of gas in the chamber.

(c) the pressure does not depend on the number of atoms of gas in the chamber.

(d) the pressure is proportional to the intensity of the gravitational field in which the chamber exists.

(e) none of the above are true.

83. According to the special theory of relativity, a space ship can exceed the speed of light

(a) if it turns into antimatter.

(b) if time is made to run backwards.

(c) if antigravity propulsion systems are used.

(d) if space is curved in the vicinity of the vessel.

(e) under no circumstances.

84. Heterodynes occur at frequencies equal to

(a) the frequencies of the input waves.

(b) even multiples of the frequencies of the input waves.

(c) odd multiples of the frequencies of the input waves.

(d) whole-number multiples of the frequencies of the input waves.

(e) the sum and difference of the frequencies of the input waves.

85. Mathematically, 1 ohm is the equivalent of

(a) 1 volt per ampere.

(b) 1 ampere per volt.

(c) 1 watt-second.

(d) 1 watt per second.

(e) 1 joule per second.

86. To convert hertz to radians per second, you must

(a) multiply by 2π.

(b) multiply by π.

(c) divide by 2π.

(d) divide by π.

(e) do nothing; the two units are equivalent.

87. Fill in the blank in the following sentence to make it *true:* “The general theory of relativity is concerned with acceleration and gravitation, and the special theory of relativity is concerned with________.”

(a) black holes and white dwarfs

(b) relative motion

(c) space travel

(d) absolute motion

(e) the gravitational collapse of the universe

88. Fill in the blank to make the following sentence *true:* “Hydrogen is changed into________inside the Sun; this process is responsible for the Sun’s energy output.”

(a) lithium

(b) copper

(c) antimatter

(d) helium

(e) ionized form

89. A typical solar battery consists of

(a) zinc-carbon or alkaline cells.

(b) photovoltaic cells.

(c) bipolar transistors.

(d) field-effect transistors.

(e) any of the above.

90. A substance in which the electrons move easily from atom to atom is

(a) an electrical solid.

(b) an electrical liquid.

(c) an electrical gas.

(d) an electrical insulator.

(e) an electrical conductor.

91. Suppose that you have a sealed, rigid container filled with air. The speed with which the molecules in the container move around depends directly on the

(a) number of atoms inside the container.

(b) mass of the air inside the container.

(c) temperature of the air inside the container.

(d) volume of the container.

(e) length of time the container has been sealed.

92. A simple objective lens refracts orange light to a slightly different extent than it refracts blue light. This is observed in a telescope as

(a) partial internal refraction.

(b) selective refraction.

(c) chromatic aberration.

(d) coma.

(e) astigmatism.

93. If 60-Hz ac is passed through a coil of wire, the resulting magnetic field

(a) has constant polarity.

(b) reverses polarity every second.

(c) reverses polarity every second.

(d) is zero.

(e) permanently magnetizes the wire.

94. Consider a straight current-carrying wire passing through a flat sheet of paper at a right angle (that is, the wire is perpendicular to the paper). What are the general shapes of the magnetic lines of flux in the plane containing the paper?

(a) Straight, parallel lines

(b) Straight lines radiating out from the wire

(c) Hyperbolas centered at the wire

(d) Circles centered at the wire

(e) It is impossible to know without more information

95. The radian is a unit of

(a) radioactivity.

(b) angular measure.

(c) temperature.

(d) electric current.

(e) electric voltage.

96. Fill in the blank to make the following sentence *true:* “The inductive reactance of a coil is________the peak amplitude of the ac passing through it.”

(a) directly proportional to

(b) directly proportional to the square of

(c) inversely proportional to

(d) inversely proportional to the square of

(e) unrelated to

97. According to the law of conservation of momentum, when multiple objects collide in an ideal system,

(a) each object has the same momentum after the collision as before.

(b) each object transfers its momentum to any object with which it collides.

(c) every object in the system has the same momentum.

(d) the total system momentum does not change as the collision takes place.

(e) all of the above are true.

98. All the energy in an ac signal is contained at a single wavelength in

(a) a square wave.

(b) a sawtooth wave.

(c) a ramp wave.

(d) a rectangular wave.

(e) none of the above.

99. Specific heat is defined in terms of

(a) degrees Celsius per kilogram.

(b) calories per gram.

(c) grams per degree Celsius.

(d) calories per gram per degree Celsius.

(e) degrees Celsius per gram per calorie.

100. Suppose that two atoms are analyzed. Atom *X* has 12 protons, 14 neutrons, and 12 electrons. Atom *Y* has 12 protons, 12 neutrons, and 10 electrons. Which of the following statements is *true?*

(a) *X* and *Y* are the same isotope of the same element; F is an ion and *X* is not.

(b) *X* and *Y* are different isotopes of the same element, and both are ions.

(c) *X* and *Y* are different elements; *Y* is an ion and *X* is not.

(d) *X* and *Y* are different isotopes of the same element; F is an ion and *X* is not.

(e) *X* and *Y* are the same isotope of different elements; F is an ion and *X* is not.

**Answers:**

1. b

2. b

3. c

4. d

5. d

6. c

7. b

8. b

9. c

10. a

11. c

12. e

13. b

14. b

15. b

16. a

17. a

18. c

19. b

20. c

21. d

22. d

23. d

24. a

25. b

26. b

27. a

28. c

29. d

30. d

31. d

32. e

33. d

34. d

35. b

36. a

37. e

38. a

39. b

40. b

41. b

42. a

43. c

44. e

45. a

46. d

47. c

48. a

49. e

50. e

51. d

52. b

53. b

54. b

55. b

56. c

57. c

58. d

59. b

60. d

61. e

62. a

63. b

64. c

65. d

66. c

67. a

68. d

69. c

70. b

71. d

72. c

73. a

74. c

75. e

76. e

77. c

78. c

79. d

80. a

81. e

82. a

83. e

84. e

85. a

86. a

87. b

88. d

89. b

90. e

91. c

92. c

93. c

94. d

95. b

96. e

97. d

98. e

99. d

100. d

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