What are the 3 basic functions of social work?

Light of the wavelength 3.0X10^-7m shines on the metals lithium, iron, & mercury, which have work functions of?

• 2.3 eV, 3.4 eV and 4.5 eV respectively. Which of these metals will exhibit the photoelectric effect? I know that if the energy calculated is larger than the work function of the metal than there is photoelectric effect, but I don't know how to solve for energy. I got that they all have photo electric effect by solving for frequency than using E=hf and if you read the problem they all have the same wavelength so they should have the same frequency according to my logic, but then again I'm usually wrong.

• Answer:

  The formula you want to make use of is E = h * c/wavelength because frequency = c/wavelength. h = 6.63 * 10^-34 c = 3 * 10^8 wavelength = 3 * 10^-7 E = 6.63 * 10^-34 * 3*10^8 / 3*10^-7 = 6.63 * 10^-19 J 1.6 * 10 - 19 J = 1 ev 6.63 * 10^-19J = x x = 4.14 eV The first two will show a photoelectric effect. The last one is just a bit shy of working.