First we have to calculate the time taken to travel the distance 30 m, is
.
Now from equation of motion,

Given,
.
As object starts from rest, so u = 0.
Substituting these values in above equation, we get
.
Thus, the acceleration is 
Answer:
The number of oxygen molecules in the left container greater than the number of hydrogen molecules in the right container.
Explanation:
Given:
Molar mass of oxygen, 
Molar mass of hydrogen, 
We know ideal gas law as:

where:
P = pressure of the gas
V = volume of the gas
n= no. of moles of the gas molecules
R = universal gs constant
T = temperature of the gas
∵
where:
m = mass of gas in grams
M = molecular mass of the gas
∴Eq. (1) can be written as:


as: 
So,

Now, according to given we have T,P,R same for both the gases.




∴The molecules of oxygen are more densely packed than the molecules of hydrogen in the same volume at the same temperature and pressure. So, <em>the number of oxygen molecules in the left container greater than the number of hydrogen molecules in the right container.</em>
Its an electrochemical cell that derives electrical energy from spontaneous redox reactions taking place within the cell.