Audio-Visual Focus Module

[Patricia Sourinphoumy Dis1C]

Hi, I kept messing up the numbers for this problem on the Audio-Visual Module. I got every other part (28 and 29) but I keep missing 30. I'll put down each of them for reference but can someone confirm what numbers they used for 30?

28. Light hits a sodium metal surface and the velocity of the ejected electron is 6.61*10^5 m.s.^-1. The work function for sodium is 150.6 kJ.mol^-1.

29. How much energy is required to remove an electron from one sodium atom?

30. What is the frequency of the incident light on the sodium metal surface?

[Joelle Tran 1K]

Hey! So for this problem, I used the E of incoming electron = KE of electron + work function.

To get the KE of the electron, I used 1.99 E-19 J since I used the KE equation .5*m*v^2. It was (.5)(9.11 E-31)(6.61 E5) when I plugged all the values in. Then, I got the work function to be 2.50 E-22 J by dividing 150.6 kJ/mol by Avogadro’s constant which is 6.022 E23 1/mol.

Adding together the KE of electron and work function into the equation, I got that the E of the incoming electron was 1.99 E-19 J. I plugged that into my manipulated Einstein equation (frequency = E/h) and got 3.01 E14 Hz.