A) 500 Hz
B) 550 Hz
C) 555.5 Hz
D) 720 Hz
Correct Answer: D
Solution :
Here in 1st case, car is source and hill is observer. Let frequency heard at hill be v? \[v'=\frac{\nu {{v}_{sound}}}{{{v}_{sound\,-\,}}{{v}_{car}}}\] \[=\,\,\,\frac{600\times 330}{330-30}\] \[=\,\,\,\frac{600\times 330}{300}\] after reflection, the hill is source and driver is observer, Let frequency heard is \[{{v}_{f}}\] \[{{v}_{f}}=v'x\,\,\frac{({{v}_{sound}}+{{v}_{car}})}{{{v}_{sound}}}\] \[=\,\,\,\,\,\frac{600\times 330}{300}\,\,\times \,\frac{(330+30)}{330}\,\] \[\Rightarrow \,\,\,\,\,\,\,\,~{{v}_{f}}=720\,\,Hz\]
You need to login to perform this action.
You will be redirected in
3 sec
