IIT JEE , AIEEE Forum - Physics , Mechanics - GOOD QUESTION IN --SOUND

bhavyageethika

The whistle of a railway engine is heard in winter at much longer distances.this is due to:

decrease in velocity of sound in winter
decrease in density of air w.r.t height from the surface of the earth
cold air absorbs much smaller energy from sound waves
increase in the density of air w.r.t height from the surface of the earth

vikalp

hey bhavyageethika

i think that the answer for this question shud be the option 3 as the sound being propagated to a larger distance has nothing to do with velocity , its the amount of dissipation of sound energy that matters !!!

but there is one more possibility of 1 also being the answer .... becoz the damping is also proportional to the velocity and in winters the velocity of the sound decreases (as temperature decreases)and hence the damping also gets lessened .......

kindly provide the answer for the query so that others also get benefitted !!!!!!!!

...................keep it cooollll...............

bhavyageethika

well ...the correct ans is 4? increase in density of air wrt to height
bcoz "in winter the density of air near the ground is more producing total internal reflection." But the velocity of sound is inversly prop to density....& density of moist air is less than that of dry air hence in winter velocity of sound is more ....then why not option 2 the answer. AND...acc to the" book " what has total internal reflection got to do with velocity.
do you think the ans is correct????

bhavyageethika

WHAT"S WRONG ........NO REPLY

vikalp

hey bhavyageethika ....
first of all i have never heard of a concept like "total internal reflection" in sound waves , it is for the light waves ......so i dont think this book's answer can satisfy me ...then again i still hold my original opinion about the question and will still say that what i had discussed earlier is right in my view .....

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