A rocket was flying at 50 [m/s]. Then they fire up the engines and it accelerates at 4 [m/s/s]. How much time does it take for the rocket to reach a final speed of 80 [m/s]?

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:

current and voltage can both be different in different parts of a circuit so it matters where you place the ammeter and voltmete