Calculate the energy of a photon emitted when an electron in a hydrogen atom undergoes a transition from n=7 to n=1

Respuesta :

Answer : The energy of photon = [tex]21.369\times 10^{-19}J[/tex]

Solution : Given,

Final energy level = 1

Initial energy level = 7

Formula used :

[tex]\frac{1}{\lambda}=R[ \frac{1}{n^2_{final}}- \frac{1}{n^2_{initial}}][/tex]    ..........(1)

where,

[tex]\lambda[/tex] = wavelength

R = Rydberg's constant = 1.0974 [tex]\times 10^7m^{-1}[/tex]

[tex]n_{final}[/tex] = final energy level

[tex]n_{initial}[/tex] = initial energy level

Now put all the given values in above formula (1), we get the value of wavelength.

[tex]\frac{1}{\lambda}=1.0974\times 10^7m^{-1} [\frac{1}{1^2}- \frac{1}{7^2}][/tex] =  [tex]1.0750\times 10^7m^{-1}[/tex]

[tex]\lambda=0.9302\times 10^{-7}m[/tex]

Now we have to calculate the energy of photon by using formula,

[tex]E=\frac{h\times c}{\lambda}[/tex]

where,

E = energy

h = planck's constant = [tex]6.626\times 10^{-7}Js[/tex]

c = speed of light = [tex]3\times 10^8m/s[/tex]

[tex]\lambda[/tex] = wavelength

put all the values in this formula, we get the energy of photon.

[tex]E=\frac{6.626\times 10^{-7}Js\times 3\times 10^8m/s}{0.9302\times 10^{-7}m}[/tex] = [tex]21.369\times 10^{-19}J[/tex]