problem solving calculation problems. (1 Viewer)

[Haku]

question:

1. a) the energy needed to remove an electron from metallic sodium is 2.28eV. Does sodium show a photoelectric effect for red light, with wavelength=60nm?
b) what is the cutoff wavelength for photoelectric emission from sodium, and to what color does this wavelength correspond?

2. incident photons strike sodium surface haveing a work function of 2.2eV, causing photoelectric emission. The stopping potential is 5.0V. what is the wavelength of the incident photon?

 

[helper]

Use

a) Is that value suppose to be 600nm?
c=f * wavelength, to find frequency
E=hf to find Energy of a red light photon.
Convert Joules to electron volts

If greater than 2.28eV then photoelectric effect will occur.

b) is same formula but backwards. I would do b first and then if 60nm is a smaller wavelength than the wavelength in b then photo electric effect will occur.

Q 2 same as 1b

 

[Haku]

wow, thanks dude,

u always help me out when i am in a pinch.

may i add u on msn messenger?