Sound of freqeuncy 1000 Hz from a stationary source is reflectd form an object approaching the source is 30 ms^(-1), back to a stationary observer located at the source. The speed of sound in a air is 330 ms^(-1). The frequency of the sound heard by the observer is :

Sound of freqeuncy 1000 Hz from a stationary source is reflectd form a

1.	Sound of freqeuncy 1000 Hz from a stationary source is reflectd form an object approaching the source is 30 ms^(-1), back to a stationary observer located at the source. The speed of sound in a air is 330 ms^(-1). The frequency of the sound heard by the observer is :
Answer» 1000 Hz 1100 Hz 1200 Hz 1090 Hz Solution :The frequency of sound from the stationary source reaches the OBJECT which is approaching towards the source is `v'=v_(0)((v+v_(0))/(v))` When `v_(0)`= frequency of source v= SPEED of sound in AIR `v_(0)`= speed of the object The frequency of reflected sound from the object heard by the stationary observer located at the source is `v''=v''((v)/(v-v_(0)))=v_(0)((v+v_(0))/(v-v_(0)))` `=1000 ((330+30)/(330-30))=1200 Hz`