# ques:the speed of sound in oxygen at a certain temp is 460 ms-1 .the speed of sound in he at same temp will be (assume both gases to be ideal)a)460 ms -1                        c)650 ms-1b)500 ms  -1                       d)330 ms-1ques:an athele in the olympics games covers a distance of 100 m in 10 s.his kinetic energy can be estimated to be in the rangea)200j-500j                       c)2x105j-3x105jb)20,000j-50,000j               d)2,000j-5,000jthanks

28 Points
14 years ago

Dear Charu Gupta,

Ans;

Qsn no 1

the speed of sound in a gas is V=(γRT/M)^(.5)

So if T is constant, We have V∞(γ/M)^.5

for O2 γ=7/5, M=32

For He γ=5/3, M=4;

hence the velocity in He is=velocity in O2×√[(5/3 ÷4)(32÷7/5)]

=1419.6 m/s

hence none of the options is correct.

Question 2

The kinetic energy is mass dependent which you have not given and hence the KE can't be calculated using your data.

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