chapter 24 physics 101

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

a

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

a

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.

a

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

a

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

a

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

a

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

a

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

a

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

a

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

a

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

a

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

b

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

b

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

b

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.

b

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

b

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

b

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.

b

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

b

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

b

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

b

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

b

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

b

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

c

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

c

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

c

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

c

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.

c

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

c

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

c

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

c

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

c

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

c

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

c

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

c

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

c

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

c

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

c

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

c

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.

c

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.

c

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.

c

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

c

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

d

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

d

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

d