red light from a He-Ne laser is at 590.5 nm in the air. it is fired at an angle of 31.0 to horizontal at a flat transparent crys
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Answer:
68.6 m/s
Explanation:
v = Speed of sound in air = 343 m/s
u = Speed of train
= Actual frequency
From the Doppler effect we have the observed frequency as
When the train is approaching
When the train is receeding
Dividing the above equations we have
The speed of the train is 68.6 m/s