Answer: unknown so the second one
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Answer:
The pressure is 
Explanation:
From the question we are told that
The initial pressure is 
The temperature is 
Let the first volume be
Then the final volume will be 
Generally for a diatomic gas

Here r is the radius of the molecules which is mathematically represented as

Where
are the molar specific heat of a gas at constant pressure and the molar specific heat of a gas at constant volume with values

=> 
=> 
=> ![P_2 = [\frac{1}{2} ]^{\frac{7}{5} } * 11.2](https://tex.z-dn.net/?f=P_2%20%20%3D%20%20%5B%5Cfrac%7B1%7D%7B2%7D%20%5D%5E%7B%5Cfrac%7B7%7D%7B5%7D%20%7D%20%2A%2011.2)
=> 
Answer:
A) Propagation of pressure fluctuations in a medium
B) air is the medium in which the wave is transported,
Explanation:
Part A.
A sound wave is a longitudinal oscillation of the molecules that forms in a material medium, they can be solid, liquid or gases, therefore the wave propagates in the same direction as the oscillation of the particles.
The most correct answer is:
* Propagation of pressure fluctuations in a medium
Part b
air is the medium in which the wave is transported, otherwise it cannot propagate
The presence of helium gas indicates the radioactive sample is most likely decaying by α-decay, or alpha decay. α-decay is the type of radioactive decay in which an atomic nucleus emits α particles. α particles are Helium nuclei. So the correct answer would be α-decay.