Just like any other gas or mixture of gases, the gas molecules are
zipping around in all different directions and with a whole range of
different speeds.
Those that happen to be moving at a speed greater than the Earth's
"escape velocity", AND are pointed away from Earth, AND don't hit
any other molecules before they escape, are lost.
With the combination of Earth's escape velocity, and the temperatures,
thickness, and density of the atmosphere, that process happens slowly
enough to have maintained an atmosphere around this planet until now.
Personally, I hope it hangs around for a while longer. But with the constant
increase in temperature that's been going on, you never know . . .
Answer: acceleration is equal to the change in velocity per unit time in seconds.
a= ∆v / t = vf - vi / t
Explanation: change in velocity or ∆v can be expressed as (vf - vi)
Answer:
D) 4
Explanation:
Roots of a polynomial must be factors of the last term.
In this case, the factors of 6 are +1, -1, +2, -2, +3, -3, +6, -6. The only factor that doesn't show up, given the options, is 4. This means that D is the correct answer.
Answer : The energy of one photon of hydrogen atom is, 
Explanation :
First we have to calculate the wavelength of hydrogen atom.
Using Rydberg's Equation:
Where,
= Wavelength of radiation
= Rydberg's Constant = 10973731.6 m⁻¹
= Higher energy level = 3
= Lower energy level = 2
Putting the values, in above equation, we get:
Now we have to calculate the energy.
where,
h = Planck's constant = 
c = speed of light = 
= wavelength = 
Putting the values, in this formula, we get:
Therefore, the energy of one photon of hydrogen atom is,
