Question

Which of the following photons has the lowest energy? a. a photon from an Ar+ laser with l = 514.5 nm b. a photon from a He–Ne laser with l = 633 nm c. a photon from a Kr+ laser with l = 647 nm d. a photon from a Nd:YAG laser with l = 1,064 nm e. a photon from an ArF laser with l = 193 nm

Answer 1

Photons have nothing to do with respect to which atom they become, since photons are units of enery... so

E = hc/WL

h and c are constants, so

E 1/WL proportional

so

The larger Wl, the smaller E

a. a photon from an Ar+ laser with l = 514.5 nm

b. a photon from a He–Ne laser with l = 633 nm

c. a photon from a Kr+ laser with l = 647 nm

d. a photon from a Nd:YAG laser with l = 1,064 nm

e. a photon from an ArF laser with l = 193 nm

the Nd:YAG laser will have a lowest energy, since it has the largest Wavelength