Answer: 
Explanation:
Given
Volume of air 
Temperature of air 
Increase in temperature 
Specific heat for diatomic gas is 
Energy required to increase the temperature is
![\Rightarrow Q=nC_pdT\\\\\Rightarrow Q=n\times \dfrac{7R}{2}\times \Delta T\\\\\Rightarrow Q=\dfrac{7}{2}nR\Delta T\\\\\Rightarrow Q=\dfrac{7}{2}\times \dfrac{PV}{T}\times \Delta T\quad [\text{using PV=nRT}]](https://tex.z-dn.net/?f=%5CRightarrow%20Q%3DnC_pdT%5C%5C%5C%5C%5CRightarrow%20Q%3Dn%5Ctimes%20%5Cdfrac%7B7R%7D%7B2%7D%5Ctimes%20%5CDelta%20T%5C%5C%5C%5C%5CRightarrow%20Q%3D%5Cdfrac%7B7%7D%7B2%7DnR%5CDelta%20T%5C%5C%5C%5C%5CRightarrow%20Q%3D%5Cdfrac%7B7%7D%7B2%7D%5Ctimes%20%5Cdfrac%7BPV%7D%7BT%7D%5Ctimes%20%5CDelta%20T%5Cquad%20%5B%5Ctext%7Busing%20PV%3DnRT%7D%5D)
Insert the values

So, first the formula of Impulse is
I = force * time
We have force but no time.
Then, find time.
Next find acceleration,
F = mass * acceleration
5 = 3 * a
1.67 m/s^2
Next find time,
Acceleration = change in velocity / time
Change in velocity is velocity final - velocity initial
1.67 = 3 - 9 / time
Time = 3.6 s (round to 2 s.f.)
Lastly,
Impulse = force * time
Impulse = 5 * 3.6
Impulse is 18 Ns
Let say the point is inside the cylinder
then as per Gauss' law we have

here q = charge inside the gaussian surface.
Now if our point is inside the cylinder then we can say that gaussian surface has charge less than total charge.
we will calculate the charge first which is given as


now using the equation of Gauss law we will have


now we will have

Now if we have a situation that the point lies outside the cylinder
we will calculate the charge first which is given as it is now the total charge of the cylinder


now using the equation of Gauss law we will have


now we will have
the answer is (a) molecules