Its have a classification of light and heavy crude oil
Answer:
The wavelength of the light emitted by a hydrogen atom for the given transition is 2166 nm.
Explanation:
The energy of nth energy levels of the H atom is given as:

Energy of the seventh energy level = 


Energy of the seventh energy level = 


Energy of the light emitted will be equal to the energy difference of the both levels.


Wavelength corresponding to energy E can be calculated by using Planck's equation:


The wavelength of the light emitted by a hydrogen atom for the given transition is 2166 nm.
The Roman numerals in a cation's name indicate: THE POSITIVE CHARGE ON THE CATION
Cations are metallic atoms that loosely hold it electrons, making it easy to lose electrons.
The Roman numerals in a cation's name not only indicates the charge on the cation but it makes it easier to distinguish cations that share the same metal name.
The answer to your equation is c