Why is it significant that the color emitted from the hydrogen emission spectrum is not white?

The color emitted from a hydrogen spectrum is not white because only colors with certain energy levels can be observed.

Explanation:

White light is generally a combination of seven colors having different wavelengths from the range of 400nm to 700nm, with violet having the wavelength of 700nm and red having 400nm. This shows that white light cannot be given a separate wavelength.

During the hydrogen emission spectrum, the colors with higher wavelengths are observed in the emission and thus there is no white light.

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.