March 28, 2024, 04:26:14 PM
Forum Rules: Read This Before Posting


Topic: Calculate the longest possible wavelength, in nanometer...  (Read 7753 times)

0 Members and 1 Guest are viewing this topic.

Offline zerox0o

  • Regular Member
  • ***
  • Posts: 13
  • Mole Snacks: +0/-2
Calculate the longest possible wavelength, in nanometer...
« on: September 19, 2009, 03:43:47 PM »
If it takes   3.92 × 10−19 J   of energy to eject an electron from the surface of a certain metal, calculate the longest possible wavelength, in nanometers, of light that can ionize the metal.

How do I do this? I am really clueless... ???

thank you!!!

Offline DrCMS

  • Chemist
  • Sr. Member
  • *
  • Posts: 1296
  • Mole Snacks: +210/-81
  • Gender: Male
Re: Calculate the longest possible wavelength, in nanometer...
« Reply #1 on: September 19, 2009, 03:53:38 PM »
How do you calculate the energy of light of a particular wavelength?  Hint Planck's constant is needed.

Offline zerox0o

  • Regular Member
  • ***
  • Posts: 13
  • Mole Snacks: +0/-2
Re: Calculate the longest possible wavelength, in nanometer...
« Reply #2 on: September 19, 2009, 04:00:46 PM »
How do you calculate the energy of light of a particular wavelength?  Hint Planck's constant is needed.

(energy) = (Planck constant)(frequency) - (work function)

(speed of wave) = (frequency)(wavelength)

E = hc/λ - φ
λ = hc/(E + φ)

k i got it! thanks :D
 
« Last Edit: September 19, 2009, 04:17:54 PM by zerox0o »

Sponsored Links