Number of moles of the gas, Temperature and the volume of the gas.
<u>Answer:</u> The longest wavelength of light is 656.5 nm
<u>Explanation:</u>
For the longest wavelength, the transition should be from n to n+1, where: n = lower energy level
To calculate the wavelength of light, we use Rydberg's Equation:

Where,
= Wavelength of radiation
= Rydberg's Constant = 
= Higher energy level = 
= Lower energy level = 2 (Balmer series)
Putting the values in above equation, we get:

Converting this into nanometers, we use the conversion factor:

So, 
Hence, the longest wavelength of light is 656.5 nm
<span>Double displacement reaction is your answer.</span>
The sub-atomic particles of an atom are the proton, electron and the neutron. An electron has a charge of -1 and a smaller
mass than a proton. Proton has the same mass with the neutron. The ratio
between the mass of a proton and an electron is about 2000. An electron has an
equal value but negative charge with the proton.