What does the Doppler Principle explain about wave frequency?

What does the Doppler Principle explain about wave frequency?

• A. The frequency remains constant regardless of movement
• B. The frequency of a wave is relative to the motion between the source and the observer
• C. The frequency increases with distance
• D. The frequency decreases with time

Answer: (B)

The Doppler Principle describes how the frequency of a wave changes relative to the motion between the source of the wave and the observer. When the source of the wave is moving toward the observer, the waves are compressed, resulting in a higher frequency or pitch. Conversely, if the source moves away from the observer, the waves are stretched, leading to a decrease in frequency. This principle is commonly observed with sound waves and is also applicable to light waves. In the context of speed measurement devices, understanding this principle is crucial as it explains how speed can be determined through the changes in frequency of the detected waves.

The Doppler Principle describes how the frequency of a wave changes relative to the motion between the source of the wave and the observer. When the source of the wave is moving toward the observer, the waves are compressed, resulting in a higher frequency or pitch. Conversely, if the source moves away from the observer, the waves are stretched, leading to a decrease in frequency. This principle is commonly observed with sound waves and is also applicable to light waves. In the context of speed measurement devices, understanding this principle is crucial as it explains how speed can be determined through the changes in frequency of the detected waves.