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Consider a souce of sound `S`, and an observer/detector `D`. The source emits a sound wave of frequency `f_0`. The frequency observed by `D` is found to be (i) `f_1`, if `D` approaches `S` and `S` is stationary (ii) `f_2`, if `S` approaches `S` and `S` is stationary (iii) `f_3`,if both `S` and `D` and `D` is stationary Speed In all three cases, relative velocity of `S` wrt `D` is the same. For this situation which is incorrect?A. `n_1=n_2=n_3`B. `n_1ltn_2`C. `n_3gtn_0`D. `n_3` lies between `n_1` and `n_2` |
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Answer» Correct Answer - B::C::D When observer `P` approaches the statinary source at speed `v`. `n_1=(V+n)/(V)xxn_0` .(i) (V is speed of sound) When source `S` approaches the stationary observer `P` at speed `v` `n_2=(V)/(V-v)xxn_0` ..(ii) Thus, `n_2gtn_1`, i.e., choice (b) is correct when both `S` and `P` approach each other with speed `(v)/(2)` `n_3=(V+((v)/(2)))/(V-((v)/(2)))n_0` .(iii) Hence `n_3gtn_0` and `n_3` lies between `n_1` and `n_2`. |
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