Question

You are in your car when you hear a fire truck blasting its siren. The siren emits sound at a fixed frequency. Under what conditions will the siren sound higher-pitched to your ear?

A) Only when the fire truck is driving towards your stationary car.

B) Only when you are driving your car towards the stationary fire truck.

C) Only when your car and the fire truck are driving directly towards one another.

D) Whenever and however your car and the fire truck are getting closer to each other.

E) The siren will not sound higher-pitched in any of these situations.

Answer 1

C) Only when your car and the fire truck are driving directly towards one another. The siren will sound higher-pitched when your car and the fire truck are driving directly towards one another.

Step-by-step explanation:

The siren will sound higher-pitched when your car and the fire truck are driving directly towards one another. This is known as the Doppler effect, which is the change in frequency or pitch of a sound wave as the source of the sound wave moves relative to the observer.

When the fire truck is driving towards your stationary car, the sound waves are compressed and the frequency of the siren appears higher, resulting in a higher-pitched sound. On the other hand, when the fire truck is driving away from your stationary car, the sound waves are stretched and the frequency of the siren appears lower, resulting in a lower-pitched sound.

Therefore, the correct answer is C) Only when your car and the fire truck are driving directly towards one another.