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Paragraph: Two trains A and B are moving with speeds 20 ~m / s and 30 ~m / s , respectively in the same direction on the same straight track, with B ahead of A . The engines are at the front ends. The engine of train A blows a long whistle. Assume that the sound of the whistle is composed of components varying in frequency from f₁=800 ~Hz to f₂=1120 ~Hz , as shown in the figure. The spread in the frequency (highest f

Options

  1. A310 ~Hz
  2. B330 ~Hz
  3. C350 ~Hz
  4. D290 ~Hz

Correct answer

A. 310 ~Hz

Step-by-step solution

For the passengers in train B , observer is receding with velocity 30 ~m / s and source is approaching with velocity 20 ~m / s . array ll & f₁^ =800 ( 340-30 340-20 )=775 ~Hz and & f₂^ =1120 ( 340-30 340-20 )=1085 ~Hz array Spread of frequency =f₂^ -f₁^ =310 ~Hz The correct option is (a).

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