Homework Help: physics

Posted by samuel on Tuesday, May 10, 2011 at 12:10am.

Light falls on a photoelectric surface that has a work function of 2.90 eV. If the voltage required to stop the ejected electrons is 0.210 V, what is the wavelength of the incident radiation?

physics - drwls, Tuesday, May 10, 2011 at 12:52am
The energy provided by a photon is
e*(Work function) + e*(stopping voltage)
= (1.602*10^-19 C)*(3.11 J/C)
= 4.98*10^-19 joules

Set that equal to h*c/(wavelength) and solve for wavelength.

Wavelength = 6.62*10^-34*3.00*10^8/4.98*10^-19
= 3.99*10^-7 m = 399 nanometers (violet)

Answer this Question

Related Questions

college: Chemistry - I need help on this homework problem and I do not ...
Physics - The work function for potassium and cesium are 2.25 and 2.14 eV, ...
Physics - The "work function", or the minimum energy needed to eject ...
Gen Chem - Light of wavelength 272 nm shines on a piece of magnesium metal. What...
Physics - - The work function of cesium surface is 2.0eV (a)find the maximum ...
Physics - Electrons are ejected from a photoelectric cell with a maximum kinetic...
physics - A metallic surface emits photo electrons when green light falls on it...
Chemistry - A laser emitting light with a wavelength of 480 nm is directed ...
physics - A metallic surface emits photo electrons when green light falls on it...
Physics - In the photoelectric effect, what happens to the stopping voltage when...

For Further Reading

First Name:
School Subject:
Answer: