Answer : The correct option is, (B) 
Solution :
According to the Graham's law, the rate of effusion of gas is inversely proportional to the square root of the molar mass of gas.
or,
..........(1)
where,
= rate of effusion of unknown gas = 
= rate of effusion of oxygen gas = 
= molar mass of unknown gas = ?
= molar mass of oxygen gas = 32 g/mole
Now put all the given values in the above formula 1, we get:
The unknown gas could be carbon dioxide 
that has approximately 44 g/mole of molar mass.
Thus, the unknown gas could be carbon dioxide
E = HF, where H is Planck's constant, 6.63 x 10 - 34 j.s
A process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one thus equalizing the concentrations on each side of the membrane. I hope this helps :D
Answer:
speed of plane in still air = 252 mph
speed of wind = 42 mph.
Explanation:
Given:
Distance travelled by the small plane = 245
Time taken to fly 245 miles = 1 hour and 10 minutes.
Time taken for return trip = 50 minutes.
To Find:
speed of the wind=?
The speed of the plane in still air=?
Solution:
We Know that
=>
=>
=>
=>210 mph against wind
on way back
=>
=>
=>
=> 294
Now
294 = plane +wind------------------------(1)
210 =plane - wind-------------------------(2)
Solving (1) and (2)
2 plane = 504
plane = 252
plane = 
So substituting plane value in eq(2) we get,
210 =252 - wind
wind = 42 mph
