Dr_Beula_PhD Posted May 15, 2006 Share Posted May 15, 2006 Hey there Just wondering if anyone can help me,I've had a question about work function of a metal with a certain wavelength and velocity given but no mass of electron,can this be done??? Cheers Beula P.S anyone into forensic science? Link to comment Share on other sites More sharing options...
swansont Posted May 15, 2006 Share Posted May 15, 2006 Velocity of what? I don't think you've given enough information to decide what question is being asked. If the wavelength given is the threshold or cutoff wavelength, then [math]E=\frac {hc}{\lambda}[/math] The mass of the electron is not needed in this case. But it depends on what you've been given. Link to comment Share on other sites More sharing options...
Dr_Beula_PhD Posted May 15, 2006 Author Share Posted May 15, 2006 Ok here's the question: Light of wavelength 0.50 x 10-6 m falls on a metal surface and results in emission of electrons of velocity 6.0 x 105 m s-1. Calculate the work function of the metal in Joules per electron. Link to comment Share on other sites More sharing options...
swansont Posted May 15, 2006 Share Posted May 15, 2006 Ok here's the question:Light of wavelength 0.50 x 10-6 m falls on a metal surface and results in emission of electrons of velocity 6.0 x 105 m s-1. Calculate the work function of the metal in Joules per electron. OK' date=' you do need the mass so you can calculate the KE of the electron. Typically that's assumed to be known, as it's a constant. 9.11 x 10[sup']-31[/sup] kg Link to comment Share on other sites More sharing options...
Dr_Beula_PhD Posted May 16, 2006 Author Share Posted May 16, 2006 Ah fantastic!!Thank you very much:-) I can now relax and if a question comes up like this in my exam I should be able to do it! Beula Link to comment Share on other sites More sharing options...
swansont Posted May 16, 2006 Share Posted May 16, 2006 Post your work if you'd like for me/us to double-check it. Link to comment Share on other sites More sharing options...
Dr_Beula_PhD Posted May 16, 2006 Author Share Posted May 16, 2006 Ah cool!Thank you very much:-) That question was on one of the past papers for my course and while revising came across it and was abit stuck! I do have more projects planned though so when I get near to finishing them I shall post them up if thats cool? Link to comment Share on other sites More sharing options...
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