A vibrating tuning fork tied to the end of a string 1.988 m long is whirled round a circle. If it makes two revolutions in a second, calculate the ratio of the frequencies of the highest and the lowest notes heard by an observer situated in the plane of the tuning fork. Valocity of sound is 350 m/s.

Explanation

Here source is revolving in a circle.
Let velocity of source = `v_(s)`
The frequency heard by observer is maximum when fork/source is approaching the observer/listener. The frequency is minimum when the fork/source is moving away from the observer/listener.
`therefore` Maximum frequency, `upsilon _(1)=(vupsilon)/(v-v_(s))`
Minimum frequency, `upsilon _(2)=(vupsilon)/(v+v_(s))`
`therefore (upsilon_(1))/(upsilon_(2))=(v+v_(s))/(v-v_(s))`
`v_(s)=romega=rxx2pixxf_(0)=1.988xx2xx3.14xx2=25ms^(-1)`
`therefore (upsilon_(1))/(upsilon_(2))=(350+25)/(350-25)=(375)/(325)-(15)/(13)`
`therefore ("Highest frequency")/("Lowest frequency")=(15)/(13)`