Physics questions

Does anyone know how to solve this 2 questions?

The first question:
Use R = ρ x L/A

We have the diameter so half of this will be the radius. We can then use this to find the area

R = 1.0 × 10–6 x 2/π(1 x 10-3)2

R = 2/π.

Question 2:
The formula for calculation of Root mean square velocity is sq. root 3RT/M since nitrogen has a lower mass it will have a greater R.M.S(as mass is inversely related to velocity).
The kinetic energy will be the same for both as the temperature is the same for both.
Answer is thus D.
this is how i did if anyone has another way please share.
hope it helps:)