Question

a student takes notes in class.
sound waves
i created by a vibration
a vibration: something that causes air molecules to move back and forth quickly and steadily
ii move through a medium
a. solid
b. liquid
c. gas

which line of her notes contains an error?
○ i
○ ia
○ ii b
○ ii c

Explanation:

To determine the error, we analyze each part:

• Line I: Sound waves are created by vibrations (correct, as vibrations generate sound by disturbing air molecules).
• Line IA: A vibration is a rapid back - and - forth motion of an object, which causes air molecules to move quickly and steadily (this is a misdefinition. A vibration is the oscillation of the source, and the air molecules oscillate around their equilibrium positions, not just "something that causes air molecules to move...". But wait, actually, the error is in the options given? Wait, no, looking at the options, the lines are I, IA, IIB, IIC. Wait, line II: Sound waves move through solids, liquids, and gases (all are mediums, so II A, B, C are correct as mediums). Line IA: The description of vibration is incorrect. A vibration is the oscillatory motion of the source (like a tuning fork vibrating), and it causes air molecules to vibrate (oscillate) around their rest positions, not just "move back and forth quickly and steadily" as a definition of vibration. But among the options, the error is in line IA? Wait, no, wait the options: the question is which line has an error. Wait, line I: correct (sound from vibration). Line IA: the definition of vibration is wrong. Because a vibration is the oscillatory motion of the object, not "something that causes air molecules...". So line IA has the error.

Answer:

IA