Who among the following scientists has not done any important work on gases?

The ratio of $\frac{C_p}{C_v}$ for inert gases is

Consider the following statements: For diatomic gases,the ratio $C_p/C_v$ is equal to:
$1$. $1.40$ (lower temperature)
$2$. $1.66$ (moderate temperature)
$3$. $1.29$ (higher temperature)
Which of the above statements are correct?

What is the difference between a barometer and a manometer?

Between $NH_3$ and $CO_2$,which one will diffuse faster? What will be the ratio of their rates of diffusion?

Pressure of a gas in a vessel can be measured by