The Doppler effect states that the frequency of sound increases as it approaches you and decreases as it goes away from you.

Since it is coming towards you, the pitch will appear to be higher.

When the ambulance passes the man, there is blue shift according to the Doppler effect. That means that the perceived frequency will be lower than the given one. Only one answer choice has a lower observed frequency than the actual frequency: .

When the ambulance approaches the man, there is red shift according to the Doppler effect. That means that as it approaches, the observed frequency increases. There is only one answer choice with a higher observed frequency than the actual frequency: .

The Doppler effect states that the frequency of sound shifts proportionally to its velocity, either moving towards you or away from you. As it moves towards you, the perceived frequency increases. As it moves away, the perceived frequency decreases. The only time you will hear the correct frequency is when the observer and sound source are directly aligned, so that the frequency is neither increased nor decreased.

Change in frequency due to relative motion is described by the Doppler effect, given by the equation:

The numerator terms are summed when the observer is moving toward the source. The denominator terms are summed if the source is moving away from the observer. You and your friend are both moving with the same velocity in the same direction, meaning that the source (friend) is moving toward the observer (you) AND the observer (you) is moving away from the source (friend). The result is that both the numerator and denominator terms will be subtracted.

The fraction simplified to one. The perceived frequency is equal to the transmitted frequency.

Since a microwave is a part of the electromagnetic spectrum, its velocity will be equal to the speed of light:

Any wave on the electromagnetic spectrum will have the same velocity, though their wavelengths and frequencies will vary, defining their individual characteristics.

Both of these waves are on the electromagnetic spectrum. Any wave on the spectrum will have the same speed, the speed of light.

Radio waves, microwaves, infrared waves, visible light, ultraviolet light, and gamma rays are all on the spectrum. They all have the same ultimate speed, but vary in their wavelengths, frequencies, and energy levels.

The relationship between wavelength, frequency, and velocity is:

In this case, because infrared light is a part of the electromagnetic spectrum, we would use  for .

We are given the speed of light and the frequency of the photon. Using these values, we can solve for the wavelength.

The relationship between velocity, frequency, and wavelength of a waveform is given by the formula:

In this case, we are dealing with an electromagnetic wave. All electromagnetic waves travel at the same velocity: the speed of light.

Using this value and the given frequency of the wave, we can solve for the wavelength.

Wavelength is traditionally reported in nanometers, corresponding to .

Any wave on the electromagnetic spectrum will travel at the same constant speed, the speed of light. Each type of wave is determined by changes in the frequency, wavelength, and energy, but these factors always reflect a constant velocity. The types of waves in the electromagnetic spectrum are radio waves, microwaves, infrared light, visible light, ultraviolet light, X-rays, and gamma rays. Radio waves will have the largest wavelength, smallest frequency, and lowest energy. Gamma rays will have the smallest wavelength, highest frequency, and greatest energy.

The inverse relationship between frequency and wavelength means that the velocity can remain constant.