Most Important Selected Qs for JEE AdvancedPhysicsWaves and Sound
A source is moving across a circle given by the equation x^2+y^2=R^2 , with constant speed 330 6 3 ~m / s , in anti-clockwise sense. A detector is at rest at point ( 2 R , 0 ) w.r.t. the centre of the circle. If the frequency emitted by the source is f and the speed of sound, c=330 ~m / s . Then
Options
- Athe position of the source when the detector records the maximum frequency is (+ 3 2 R,- R 2 )
- Bthe coordinate of the source when the detector records minimum frequency is (0, R)
- Cthe minimum frequency recorded by the detector is 6 3 +6 3 f
- Dthe maximum frequency recorded by the detector is 6 3 6 3 - f
Correct answer
D. the maximum frequency recorded by the detector is 6 3 6 3 - f
Step-by-step solution
Sound emitted by source at A will result in maximum frequency while sound emitted by source at B will result in minimum frequency. Time taken by sound to reach from A to detector = 2 R 60^ 330 aligned & Angle travelled by source by this = 330 6 3 R 2 R 60^ 330 = 6 & f_ = ( 330 330- 330 6 3 ) f ; f_ = ( 330 330+ 330 6 3 ) f aligned