Two fire trucks with sirens speeds towards and away from an observer. which statement is true involving the doppler effect observed by the observer? a) the doppler effect is not observed by the observer b) due to the doppler effect, the fire truck traveling towards the observer is not heard c) the fire truck traveling away from the observer produces a lower than normal apparent siren frequency d) the fire truck traveling towards the observer produces a lower than normal apparent siren frequency

The correct answer is C.

Explanation:

Doppler effect is a  phenomenon in which there is a relative motion between the source and the observer then there will be change in the frequency of the wave.

For example,when the source and the observer are moving each other then the frequency increases in this case. When the source and the observer are moving away from other then the frequency decreases in this case.

In the given problem, two fire trucks with sirens speeds towards and away from an observer. In this case, the fire the fire truck traveling away from the observer produces a lower than normal apparent siren frequency

Therefore, the correct answer is C.

need to see circuit to get time constant