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AP EAMCET2013PhysicsWaves and Sound

A source of sound of frequency 640 ~Hz is moving at a velocity of 100 3 ~m / s along a road, and is at an instant 30 ~m away from a point A on the road (as shown in figure). A person standing at O, 40 ~m away from the road hears sound of apparent frequency v^ . The value of v^ is (velocity of sound =340 ~m / s )

Options

  1. A620 ~Hz
  2. B680 ~Hz
  3. C720 ~Hz
  4. D840 ~Hz

Correct answer

B. 680 ~Hz

Step-by-step solution

We know that, n^ =n [ v v-v_s ] Hence, aligned n^ & =640 [ 340 340- 100 5 ] n^ & =640 340 320 =2 340 & =680 ~Hz aligned

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