Answer : The correct option is, \(8.988\times 10^{-26}joules\)
Solution :
Formula used :
\(E=\frac{h\times c}{\lambda}\)
where,
E = change in energy
h = Planck’s constant = \(6.626\times 10^{-34}J/s\)
c = speed of light = \(2.998\times 10^{8}m/s\)
\(\lambda\) = wavelength = 2.21 m
Now put all the given values in the above formula, we get the energy of an atom.
\(E=\frac{(6.626\times 10^{-34}J/s)\times (2.998\times 10^{8}m/s)}{2.21m}\)
\(E=8.988\times 10^{-26}joules\)
Therefore, the energy of an atom is, \(8.988\times 10^{-26}joules\)