InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
A train , standing at the outer signal of a railway station blows a whistle of frequency 400 Hz in still air, (i) What is thefrequency of the whistle for a platform observer when the train (a) approaches the platform with a speed of `10ms^(-1)`, (b) recedes from the platform with a speed of `10 ms^(-1)` ? (ii) What is the speed of sound in still air can be taken as `340 ms^(-1)` . |
|
Answer» (i) Here, `v = 400 Hz, v = 340 m//s ` (a) Train approaches the platform `v _(s) 10 m//s ` `v^(1)= ( v)/( v-v_(s)) = ( 340 xx 400)/( 340- 10) = 412.12 Hz` (b) Train receds from the platform `v_(s) = 10 m //s ` `v^(1)= ( v)/( v-v_(s)) = ( 340 xx 400)/( 340+ 10) ` `= 388.6 Hz` (ii) The speed of sound in each case is the same =` 340 m //s ` |
|