{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

6.radiation key

6.radiation key - Chem 105 Nielson Recitation...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chem 105 Nielson Recitation 9/25/07 Electromagnetic radiation Photoelectric effect Atomic spectra Bohr atom 1. The yellow light given off by a sodium vapor lamp used for public lights has a wavelength of 589 nm. a. What is the frequency of this radiation? Ans. 5.09 x 10 14 s -1 b. What is the energy of one quantum or photon? Ans. 3.37 x 10 -19 J c. If in an hour’s time, the lamp emits light with a total energy of 27 J, how many photons have been emitted? Ans. 8.0 x 10 19 photons 2. Molybdenum metal must absorb radiation with a minimum frequency of 1.09 x 10 15 s -1 before it can emit an electron from its surface via the photoelectric effect. a. What is the minimum energy required to produce this effect (the threshold energy)? Ans. 7.22 x 10 -19 J b. What wavelength radiation will provide a photon of this energy? Is this visible light? Ans. 275 nm. No, this is not visible light. The range for visible light is 400-700 nm.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
c. If molybdenum is irradiated with the light of wavelength 120. nm, what is the maximum possible kinetic energy of the emitted electrons? Ans. Total energy of 120. nm light = threshold energy + kinetic energy.
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}