As a gust of wind blows across a field of grain, a wave can be seen to move across the field as the tops of the plants sway back and forth. This wave is a:
a. transverse wave.
b. longitudinal wave.
c. polarized wave.
d. interference of waves.
[Ques. 2] A horizontal wire of length 4.5 m carries a current of 5.8 A and is oriented so that the current direction is 53 S of W. The Earth's magnetic field is due north at this point and has a strength of 0.14 104 T. What is the size of the force on the wire?
a. 2.9E4 N
b. 3.4E4 N
c. 1.4E4 N
d. 2.2E4 N
e. 7.8E5 N
[Ques. 3] For a wave on the ocean, the amplitude is:
a. the distance between crests.
b. the height difference between a crest and a trough.
c. one half the height difference between a crest and a trough.
d. how far the wave goes up on the beach.
[Ques. 4] Which statement regarding the force of a magnetic field on a current-carrying wire is true?
a. The magnetic force on the wire is independent of the direction of the current.
b. The force on the wire is directed parallel to both the wire and the magnetic field.
c. The force takes its largest value when the magnetic field is parallel to the wire.
d. All of the above statements are false.
[Ques. 5] Which of the following is an example of a longitudinal wave?
a. sound wave in air
b. wave traveling in a string
c. both a and b
d. neither a nor b
[Ques. 6] A horizontal wire of length 3.0 m carries a current of 6.0 A and is oriented so that the current direction is 50 S of W. The Earth's magnetic field is due north at this point and has a strength of 0.14 104 T. What is the direction of the force on the wire?
a. out of the Earth's surface
b. toward the Earth's surface
c. due east
d. 40 S of E
[Ques. 7] When car shock absorbers wear out and lose their damping ability, what is the resulting oscillating behavior?
a. underdamped
b. critically damped
c. overdamped
d. hyperdamped
[Ques. 8] A current-carrying wire of length 52.0 cm is positioned perpendicular to a uniform magnetic field. If the current is 15.0 A and it is determined that there is a resultant force of 2.3 N on the wire due to the interaction of the current and field, what is the magnetic field strength?
a. 0.29 T
b. 0.029 T
c. 0.020 T
d. 0.38 T
e. 0.18 T
[Ques. 9] A pendulum on the Earth has a period T. The acceleration of due to gravity on Mars is less than that on the Earth, and the acceleration due to gravity on the Moon is even less. Where would the period of an identical pendulum be the least?
a. on the Earth
b. on the Moon
c. on Mars
d. The period of a pendulum would be the same on the Earth, Moon, and Mars since the period depends on the pendulum's length which is the same for identical pendula.
[Ques. 10] The direction of the force on a current carrying wire located in an external magnetic field is which of the following?
a. perpendicular to the current
b. perpendicular to the field
c. Both choices A and B are valid.
d. None of the above are valid.
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