Answer:
1.36x10^-19 J
Step-by-step explanation:
First, we need to write the bohr's equation for the energy levels:
E(n) = -1/n² * 13.6 eV
Now, the question is asking this energy in Joules, so at the end we will use the conversion of eV to Joules.
As the energy level is 4, we just replace the value of n = 4 in the equation and solve for the energy in eV first:
E(4) = -1/4² * 13.6
E(4) = -0.85 eV
Now, the conversion for eV to Joules is the following:
1 eV = 1.6022x10^-19 J
Therefore, we just need to multiply the obtained value of Energy in eV with this factor, and we have the energy in Joules as required:
E = -0.85 * 1.6022x10^-19
E = 1.36x10^-19 J
This is the energy in Joules for an electron in the level 4.