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-1

b)500 ms -1 d)330 ms-1

ques: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 range

a)200j-500j c)2x10^5j-3x10^5j

b)20,000j-50,000j d)2,000j-5,000j

thanks

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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