On top a coiled spring labeled Wave A with coils, which are widely spaced then tightly spaced then widely space. On bottom a coiled spring labeled Wave B with coils, which are widely spaced then very tightly spaced then widely space. Which statement can be made about waves A and B?

Wave A has a lower amplitude than Wave B.
Wave A has a higher amplitude than Wave B.
Wave A has a lower frequency than Wave B.
Wave A has a higher frequency than Wave B.

Wave A has a lower frequency than Wave B.

Explanation:

Frequency is the number of waves passing through the unit time.

As the statement of the question says that the coils in wave A are widely and tightly spaced.

While in wave B the coils are widely and very tightly spaced which means the number of coils is more and the frequency of wave B is more than wave A.

Therefore more coils will pass through a fixed point in unite time and more will be the frequency.  

absorption lines are where light has been absorbed by the atom thus you see a dip in the spectrum whereas.

emission spectra have spikes in the spectra due to atoms releasing photons at those wavelengths.

explanation: