Why does a siren have a lower pitch as it moves away from you?

Awave is produced in a rope. the wave has a speed of 33 m/s and a frequency of 22 hz.

Wave functions describe orbitals in a hydrogen atom. each function is characterized by 3 quantum numbers: n, l, and ml. if the value of n = 2: the quantum number l can have values from to . the total number of orbitals possible at the n = 2 energy level is .

Avoltaic cell converts chemical energy to