chapter 24 physics 101

1) Magnetic compasses reportedly were first used for navigation by A) Aristotle. B) Australian aborigines. C) Chinese sailors. D) none of the above

2) The source of all magnetism is A) tiny pieces of iron. B) tiny domains of aligned atoms. C) ferromagnetic materials. D) moving electric charge. E) none of the above

3) The force that acts between a pair of electrically-charged particles depends on A) magnitude of charge. B) separation distance. C) both of these D) neither of these

4) The force that acts between a pair of magnetic poles depends on A) magnetic pole strength. B) separation distance. C) both of these D) neither of these

5) Like kinds of magnetic poles repel while unlike kinds of magnetic poles A) attract. B) repel also. C) may attract or repel.

7) Whereas electric charges can be isolated, magnetic poles A) can also. B) cannot. C) gather in clusters. D) none of the above

8) Refrigerator magnets are typically A) short range. B) long range. C) none of these

9) If you break a bar magnet in half you'll A) destroy its magnetic properties. B) have two magnets. C) have two and a half magnets. D) none of the above

10) Surrounding every magnet is A) a magnetic field. B) an electric field. C) both of these D) neither of these

11) Surrounding every stationary electron is A) a magnetic field. B) an electric field. C) both of these D) neither of these

12) Surrounding every moving electron is A) a magnetic field. B) an electric field. C) both of these D) neither of these

13) Magnetic fields are produced by A) a tiny fraction of moving electrical charges. B) most moving electrical charges. C) all moving electrical charges.

14) Magnetism is due to the motion of electrons as they A) move around the nucleus. B) spin on their axes. C) both of these D) neither of these

15) The conventional direction of magnetic field lines outside a magnet are from A) north to south. B) south to north. C) either way

16) Magnetic field strength about a magnet is strongest where magnetic field lines are A) closer together. B) straightest. C) most curved. D) more spread.

18) The magnetic fields of a pair of nearby magnets can A) only add. B) cannot add or subtract. C) add or subtract by vector rules.

19) The end of a compass needle that points to the south pole of a magnet is the A) north pole. B) south pole. C) both of these

22) In the atoms of most materials the fields of individual electrons A) cancel one another. B) partly align. C) completely align.

25) An iron nail is more strongly attracted to the A) north pole of a magnet. B) south pole of a magnet. C) either of these D) neither of these

27) The shape of a magnetic field surrounding a current-carrying conductor is A) consistent with the inverse-square law. B) radial. C) circular. D) all of these E) neither of these

28) Magnetic field lines about a current-carrying wire A) extend radially from the wire. B) circle the wire in closed loops. C) both of these D) neither of these

29) When current reverses direction in a wire, the surrounding magnetic field A) also reverses direction. B) becomes momentarily stronger. C) contracts. D) expands.

30) When a current-carrying wire is bent into a loop, its magnetic field inside the loop A) weakens. B) becomes concentrated. C) cancels. D) none of the above

31) As the number of loops in a current-carrying wire is increased, the A) more spread out is the magnetic field. B) stronger the enclosed magnetic field. C) weaker the current. D) greater the back emf.

32) A beam of electrons passing through a magnetic field experiences maximum deflection if the direction of the beam is A) parallel to the field lines. B) perpendicular to the field lines. C) none of these

33) A beam of electrons can pass through a magnetic field without being deflected if the direction of the beam is A) parallel to the field lines. B) perpendicular to the field lines. C) none of these

35) A current-carrying coil of wire is A) a superconductor. B) a superconducting magnet. C) an electromagnet. D) a magplane in the making.

39) Magnet A has twice the magnetic field strength of Magnet B and at a certain distance pulls on magnet B with a force of 100 N. The amount of force that magnet A exerts on magnet B is A) at or about 50 N. B) exactly 100 N. C) need more information

40) Compared to the huge force that attracts an iron tack to a strong magnet, the force that the tack exerts on the magnet is A) relatively small. B) equally huge. C) inversely proportional to their masses.

44) When an electron passes through the magnetic field of a horseshoe magnet, the electron's A) speed is increased. B) direction is changed. C) both of these D) neither of these

45) The force exerted on an electron moving in a magnetic field is maximum when the electron moves A) parallel to the magnetic field. B) perpendicular to the magnetic field. C) either of these D) neither of these

46) The force a magnetic field exerts on a current-carrying wire is maximum when the wire is oriented A) parallel to the magnetic field. B) perpendicular to the magnetic field. C) either of these D) neither of these

47) A current-carrying wire in a magnetic field A) may be deflected. B) may experience a force. C) both of these D) neither of these

48) An electron beam directed through a magnetic field A) may be deflected. B) may experience a force. C) both of these D) neither of these

49) No net force acts on a loop of wire in a magnetic field when A) no current is in the loop. B) no magnetic field lines pass through the loop. C) both of these D) neither of these

52) A galvanometer can be calibrated to measure A) electric current. B) electric voltage. C) both of these D) none of these

53) Although a magnet can change the direction of travel of an electron beam, it cannot change its A) speed B) kinetic energy. C) both of these D) neither of these

55) Which force field can increase a moving electron's speed? A) electric field B) magnetic field C) both of these D) neither of these

56) Which force field can accelerate an electron? A) electric field B) magnetic field C) both of these D) neither of these

57) Over geologic history the Earth's magnetic field A) has been relatively stable. B) has increased in strength exponentially. C) has reversed direction many times. D) is unknown.

58) Solar winds headed in Earth's direction are deviated mainly by A) the upper atmosphere. B) the troposphere. C) Earth's magnetic field. D) Earth's radiation belts.

60) The intensity of cosmic rays bombarding the Earth's surface is most at the A) poles. B) mid-latitudes. C) equator.

61) An aurora borealis high above the atmosphere is due to A) disturbances in Earth's magnetic field. B) fountains of high-speed charged particles. C) trapping of charged particles by Earth's magnetic field. D) all of the above

62) Cosmic rays penetrate your body when A) safely in your home. B) outdoors. C) in mountainous regions. D) all of the above E) none of the above

63) Earth's magnetic field is A) something we've learned to live with. B) useful to pigeons but not to humans. C) protective to life on Earth.

64) Pigeons navigate primarily by A) a good memory. B) a keen sense of smell. C) magnetic sensors in their heads. D) ultra-high-pitched sounds. E) none of the above