Photoelectric Effect and Line Spectra (4E) Practice Test

A hydrogen discharge tube is analyzed with a spectrometer. Three visible emission lines are recorded at approximately 656 nm, 486 nm, and 434 nm. (Constants: $c=3.00\times 10^8,\text{m/s}$, $h=6.63\times 10^{-34},\text{J·s}$.) Based on quantized electronic energy levels, which conclusion is most consistent with observing discrete wavelengths rather than a continuous spectrum?

In a photoelectric setup, monochromatic light of frequency $f$ shines on a metal. The stopping potential is measured as $V_s$. The frequency is increased to $2f$ while the intensity is unchanged and the metal is unchanged. (Constants: $h=6.63\times 10^{-34},\text{J·s}$, $e=1.60\times 10^{-19},\text{C}$.) Which change is expected, assuming both frequencies exceed threshold?