Radio Astronomers Often Study the Radiation Emitted by a Hydrogen

Multiple Choice

Radio astronomers often study the radiation emitted by a hydrogen atom from a transition between the two hyperfine levels associated with the ground state.This radiation has a wavelength of 21 cm.What is the energy difference between the hyperfine levels? (1 eV = 1.60 × 10^-19 J)

A) 5.9 × 10^-6 eV
B) 5.9 × 10^-25 J
C) 1.7 × 10^-24 J
D) 4.7 × 10^-25 J