Explain the Doppler frequency or Doppler shift.​

it is the change in frequency of a wave in relation to an observer who is moving relative to the wave source.[1] It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842.

Explanation:

please mark brainliest thank you

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.

i need with 1.3.2 investigate cycling o2 and co2 apex

we need to see it