As you drive down the road see and heae an ambulance go by in opposite direction after it passes how is frequency?

The frequency of the sound of an ambulance siren as you drive down the road and it passes by in the opposite direction will change due to the Doppler effect.

Here's what happens:

1. Initially: As the ambulance approaches you, the sound waves emitted by its siren are compressed because the ambulance is moving towards you. This compression of the sound waves increases their frequency,

resulting in a higher-pitched sound.

2. Passing: As the ambulance passes by and moves away from you, the sound waves are stretched out due to the ambulance's motion away from you.

This stretching of the sound waves decreases their frequency, resulting in a lower-pitched sound.

3. After passing: After the ambulance has passed you and is moving away, the sound waves emitted by its siren will have a lower frequency compared to the original frequency before the ambulance approached you.

This is because the ambulance is now receding from you, and the stretching of the sound waves causes the frequency to decrease.

This phenomenon, where the frequency of a sound changes depending on the relative motion between the source of the sound and the observer is known as the Doppler effect.