Physical Science Test 2

10. On the molecular level, heat is a. Kinetic energy b. Potential energy c. Rest energy d. All of these, in proportions that depend on the circumstances

a

13. The physics of a refrigerator most closely resembles the physics of a. a heat engine b. the melting of ice c. the freezing of water d. the evaporation of water

a

14. The working substance (or refrigerant) used in most refrigerators is a a. gas that is easy to liquefy b. gas that is hard to liquefy c. liquid that is easy to solidify d. liquid that is hard to solidify

a

25. The particle easiest to remove from an atom is a(an) a. Electron b. Proton c. Neutron d. Nucleus

a

27. Superconductors a. Have no electrical resistance b. Have very little electrical resistance c. Are used in making transistors d. Have no practical applications

a

28. Electric power (P=IV) is equal to a. (current)(voltage) b. Current/voltage c. Voltage/current d. (resistance)(voltage)

a

3. Heat transfer in a vacuum can occur by a. Radiation only b. Convection only c. Radiation and convection only d. Radiation, convection, and conduction

a

30. When a magnetized bar of iron is strongly heated, its magnetization a. Becomes weaker b. Becomes stronger c. Reverses its direction d. Is unchanged

a

36. An electromagnet a. Uses an electric current to produce a magnetic field b. Uses a magnetic field to produce and electric current c. Is a magnet that has an electric charge d. Operates only on alternating current

a

38. A transformer can change a. The voltage of an alternating current b. The power of an alternating current c. Alternating current to direct current d. Direct current to alternating current

a

41. The current in a 40 W, 120 V electric lightbulb is a. 1/3 A b. 3 A c. 80 A d. 4800 A

a

5. The pressure of the earth's atmosphere at sea level is due to a. The gravitational attraction of the earth for the atmosphere b. The heating of the atmosphere by the sun c. The fact that most living things constantly breathe air d. Evaporation of water from the seas and oceans

a

42. If a 120 V electric toaster draws a current of 4 amps, what is its resistance in ohms?

a. 30 ohms

45. An amp is a unit of electrical

a. Current

6. An ice cube, whose center consists of liquid water, is floating in a glass of water. When the ice melts, the level of water in the glass a. Rises b. Remains the same c. Falls d. Any of the above, depending on the relative volume of water inside the ice cube

b

44. Which of the following statements is correct?

a. Moving electrons constitute an electric current

46. How does an electron acquire a negative charge?

a. Negative charge is a fundamental property of an electron

17. Suppose the volume of gasoline in your gas tank expands with warming temperatures. Do you now have more gasoline?

a. No, you still have the same mass of gasoline

19. Electric charge

a. Occurs only in separate parcels of 1.6 x10-19 C

43. Which of the following statements is not true?

a. Protons and electrons have equal masses

11. A heat engine takes in heat at one temperature and turns a. All of it into work b. Some of it into work and rejects the rest to a reservoir at a lower temperature c. Some of it into work and rejects the rest to a reservoir at the same temperature d. Some of it into work and rejects the rest to a reservoir at a higher temperature

b

12. In any process the maximum amount of heat that can be converted to mechanical energy a. Depends on the amount of friction present b. Depends on the intake and exhaust temperatures c. Depends on whether kinetic or potential energy is involved d. Is 100 percent

b

15. Heat is absorbed by the refrigerant in a refrigerant when it a. Melts b. Vaporizes c. Condenses d. Is compressed

b

20. A positive electric charge a. Attracts other positive charges b. Repels other positive charges c. Does not interact with other positive charges but only with negative ones d. Consists of an excess of electrons

b

21. Protons and electrons have different masses. When they are the same distance apart, the electric force between two electrons a. Is less than the force between two protons b. Is the same as the magnitude of the force between two protons c. Is greater than the force between two protons d. Any of these choices could be correct, depending on the distance between each pair of particles.

b

26. A solid conductor is one a. Whose electrons are firmly bound in place b. Whose electrons are free to move about c. That has no electrons d. That has too many electrons

b

32. Magnetic field lines provide a convenient way to visualize a magnetic field. Which of the following statements is not true? a. The path followed by an iron particle released near a magnet corresponds to a field line. b. The path followed by an electric charge released near a magnet corresponds to a field line. c. A compass needle in a magnetic field turns until it is parallel to the field lines around it. d. Magnetic field lines do not actually exist.

b

33. In a drawing of magnetic field lines, the weaker the fields is, the a. Closer together the field lines are b. Farther apart the field lines are c. More nearly parallel the field lines are d. More divergent the field lines are

b

35. The nature of the force that is responsible for the operation of an electric motor is a. Electric b. Magnetic c. A combination of electric and magnetic d. Either electric or magnetic, depending on the design of the motor

b

16. A refrigerator gives off a. Less heat than it absorbs from its contents b. The same amount of heat it absorbs from its contents c. More heat than it absorbs from its contents d. Any of these choices could be correct, depending on the circumstances

c

22. Coulomb's law for the force between electric charges belongs in the same general category as a. The law of conservation of energy b. Newton's second law of motion c. Newton's law of gravitation d. The second law of thermodynamics

c

23. The electric force between a proton and an electron a. Is weaker than the gravitational force between them b. Is equal in strength to the gravitational force between them c. Is stronger than the gravitational force between them d. Is any of these, depending on the distance between the proton and the electron

c

29. The electric energy lost when a current passes through a resistance a. Becomes magnetic energy b. Becomes potential energy c. Becomes heat d. Disappears completely

c

34. A moving electric charge produces a. Only an electric field b. Only a magnetic field c. Both an electric and a magnetic field d. Any of these, depending on its speed

c

4. The fluid at the bottom of a container is a. Under less pressure than the fluid at the top b. Under the same pressure as the fluid at the top c. Under more pressure than the fluid at the top d. Any of these, depending upon the circumstances

c

40. The resistance of a light bulb that draws a current of 2 A when connected to a 12 V battery is a. 1.67 ohms b. 2 ohms c. 6 ohms d. 24 ohms

c

8. Which of the following statements is not correct? a. Matter is composed of tiny particles called molecules. b. These molecules are in constant motion, even in solids. c. All molecules have the same size and mass. d. The differences between the solid, liquid, and gaseous states of matter lie in the relative freedom of motion of their respective molecules.

c

1. One gram of steam at 100⁰C causes a more serious burn than one gram of water at 100⁰C because the steam a. Is less dense b. Strikes the skin with greater force c. Has a higher specific heat d. Contains more energy

d

18. The charge on any electron a. Is 1 C b. Depends on the electron's mass c. Depends on the electron's size d. Is always the same

d

2. Heat transfer in a gas can occur by a. Radiation only b. Convection only c. Radiation and convection only d. Radiation, convection, and conduction

d

24. An atom consists of a a. Uniform distribution of positive charge in which electrons are embedded b. Uniform distribution of negative charge in which electrons are embedded c. Small negative nucleus surrounded at a distance by protons d. Small positive nucleus surrounded at a distance by electrons

d

31. All magnetic fields originate in a. Iron atoms b. Permanent magnets c. Stationary electric charges d. Moving electric charges

d

37. A generator is said to "generate electricity." What it actually does is act as a source of a. Electric charge b. Electrons c. Magnetism d. Electric energy

d

39. The voltage needed to product a current of a 5 A in a resistance of 40 ohms is a. 0.125 V b. 5 V c. 8 V d. 200 V

d

7. At constant pressure, the volume in a gas sample is directly proportional to a. The size of its molecules b. Its Fahrenheit temperature c. Its Celsius temperature d. Its absolute temperature

d

9. Absolute zero may be regarded as that temperature at which a. Water freezes b. All gases become liquids c. All substances become solid d. Molecular motion in a gas would be the minimum possible

d