Question

If an air their is number density n=10^-19cm^-3 and T= 300k . Justify weather this air is plasma or not ?

Answer 1

Let us calculate how many particles normal air at 300 K contain within 1 cubic centimetre:

$$N=nN_A=\frac{m}{\Mu}N_A=\frac{\rho V}{\Mu}N_A,\\\space\\ N=\frac{1.161\cdot1}{29}6.022\cdot10^{23}=2.41\cdot10^{22}\text{ cm}^{-3}.$$

This is how many particles air would contain in 1 cm³ at 300 K. Therefore, the given substance is plasma.