What is the change in energy of an atom if the wavelength of the photon absorbed by the atom is equal to 4.64 x 10-7 meters? (Planck’s constant is 6.626 x 10-34 joule seconds; the speed of light is 2.998 x 108 m/s)?

1.428 x 10-41 joules second

3.074 x 10-26 joules

3.440 x 10-19 joules/second

4.281 x 10-19 joules

10.255 x 10-49 joule second

Question

What is the change in energy of an atom if the wavelength of the photon absorbed by the atom is equal to 4.64 x 10-7 meters? (Planck’s constant is 6.626 x 10-34 joule seconds; the speed of light is 2.998 x 108 m/s)?



1.428 x 10-41 joules second 



3.074 x 10-26 joules 



3.440 x 10-19 joules/second 



4.281 x 10-19 joules



10.255 x 10-49 joule second

anonymous · Answer

Energy of photon = hv where h = Plancks constant and v = frequency. 
Increase in energy of atom = hv = 6.626*10^-34*v 
Using velocity = frequency*wavelength 
2.998*10^8 = v*4.64*10^-7 
v = (2.998/4.64)*10^15 Hz = 6.461*10^14Hz 
Therefor increase in energy of atom is: 
E = 6.626*10^-34*6.461*10^14 J 
E = 4.281*10^-19 J