10. The wavelength of light associated with the n = 2 to n = 1 electron transition in the hydrogen spectrum is 1.216✕10–7 m. By what coefficient should this wavelength be multiplied to obtain the wavelength associated with the same electron transition in the Li2+ ion?
(A) 1/9;
(B) 1/7;
(C) 1/4;
(D) 1/3;
(E) 1