Photoelectric effect, mercury vapor lamp

[korky0429]

I had a lab with photoelectric effect and we measured different colors wavelength/frequency by finding stopping voltage vs current.

Then we used no color filter and used the mercury vapor lamp and had to find the wavelength which was around 400nm. Questions were why was this wavelength the one that was measured since the light emits other wavelengths and why this was able to be emitted.

 

[TSny]

Suppose you had a bulb that emitted two colors: blue and green and that both colors are capable of ejecting electrons in the photoelectric effect. Which color would emit the most energetic electrons? Which color would correspond to the measured stopping potential?