1. A stationary police officer using a speed “radar detector” sends a signal with a frequency of 100,000 Hz. The speed of sound is 340 m/s.
2. The light waves from a distance start appear to be “blue shifted”. Is the star moving toward or away from the earth? Explain your answer.
1 . Given that frequently f= 100000 Hz
Velocity of the wave v = 340 m/s
a. We have the relationship wavelength, d = v / f
So here wavelength of the sound = 340 / 100000
= 3.4 x 10 -3 metres
b .as the vecicle is moving towards the officer,
Due to dopler effect of sound waves, the detector will recieve a reflected sound which has a higher frequency as compared to the original sound wave.
2. A blue shift is a demonstration of shifting of the frequency of the oroginal lightwave towads a higher frequency . And as per dopler effect a shift to higher frequency ( blue shift) is shown by a source or star which is moving towards the observer. So the star is moving towards the earth.
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