Question

question #17
a toy firetruck that makes a siren noise is moving toward a person that is standing still. what happens to the pitch and wavelength as it gets closer to the person?

pitch increases, wavelength decreases
pitch decreases, wavelength increases
pitch decreases, wavelength decreases
pitch increases, wavelength increases

Explanation:

For the first part about diffuse reflection, in diffuse reflection light hits a bumpy surface and bounces back at many different angles. The options about smooth - surface are incorrect as smooth surfaces are for specular reflection. For the second part, according to the Doppler effect, when a source (the firetruck) is moving towards a stationary observer, the pitch (frequency) increases and the wavelength decreases.

Answer:

The correct option for the diffuse - reflection question is: The light hits a bumpy surface and bounces back at many different angles.
The correct option for the firetruck question is: Pitch increases, wavelength decreases