In a physics laboratory, a diffraction grating with 400 lines per millimetre400\text{ lines per millimetre}400 lines per millimetre is set up in front of a light source. A student looks through the grating at a ruler placed parallel to the grating at a distance of 0.80 m0.80\text{ m}0.80 m.
A first-order bright line is observed at a position x=16 cmx = 16\text{ cm}x=16 cm from the central zero-order maximum on the ruler.
Show that the energy of a photon of wavelength 497 nm497\text{ nm}497 nm is approximately 4.00×10−19 J4.00 \times 10^{-19}\text{ J}4.00×10−19 J.
Figure 1 shows some of the energy levels of an electron in this atom.
Identify the initial and final energy levels (in 10−19 J10^{-19}\text{ J}10−19 J) for the electron transition that would cause the emission of a photon of wavelength 497 nm497\text{ nm}497 nm.
