Showyouequationscf3x10812x101525x107m250nm 9

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: tion produced? Show calculation. T=1/3 sec so f=1/T=3 Hz 6. In what part of the E‐M spectrum is the radiation in problem #5? Very long wavelength radio waves. 7. The work function ф is the amount of energy it takes to pry an electron from a metal. For copper ф = 4.5 eV. What is the lowest frequency light which can free an electron from copper? E=фq=4.5x1.6x10‐19 Joules and f=E/h so f=4.5x1.6x10‐19 /6.2x10‐34 = 1.2x1015 Hz 8. What is the wavelength of the photon in problem #7? Show you equations. λ=c/f=3x108/1.2x1015=2.5x10‐7 m=250nm 9. What part of the E‐M spectrum is the photon in problem #7? Show your logic in case you got #7 wrong. UV 10. What is the momentum p (in Kg m/s) of the photon in problem #7? Show your logic in case you got #7 wrong. Hint: If you use one system of units (m, s, Coulombs, Hz) it will come out correctly.p=E/c=hf/c=h/λ=6.2x10‐34/2.5x10‐7=2.5x10‐27kg‐m/s2 11. How does the product of the answer for #8 and #10 compare to what you expect for ΔxΔp from the uncertainty principle? λp=2.5x10‐7 x 2.5x10‐27= 6.2x10‐34 which is h (Planck’s constant) as it should be! (within a factor of 2 or so). 12. What physical property does not change when...
View Full Document

This document was uploaded on 05/29/2011.

Ask a homework question - tutors are online