Select the statement that correctly completes the description of phase difference.
phase difference describes:
o the difference in the phase angle between any two waves at any given position along the waves.
o the shift between the positions of corresponding crests of two waves of the same frequency.
o the difference in the frequencies of two waves at a given time.
o the displacement of a wave particle from its undisturbed position at the origin.

The difference in the phase angle between any two waves at any given position along the waves.

Explanation:

The phase difference between two waves is defined as the difference between its two phase angles, measured at the same time, but not always at the same point in space. In other words, the phase difference is when the waves have the same frequency, but reach their zero value at a different time.

real, smaller and upside-down.   so the answer should be b.

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.