- 323 Views
- Uploaded on

Download Presentation
## PowerPoint Slideshow about 'Gustav Robert Kirchhoff' - lucretia

**An Image/Link below is provided (as is) to download presentation**

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

Vital Statistics

- Born: 12 March 1824, Königsberg, Prussia
- Christened: 11 April 1824
- Father: Friedrich Kirchhoff (lawyer)
- Mother: Johanna Henriette Wittke
- Married: 1847, to Clara Richelot (his math professor’s daughter – good reason to study math!)
- Died: 17 October 1887, Berlin
- Temple work: Done several times, 1929-2001. (Often just sealed to Mr. and Mrs. Kirchhoff – good reason to study physics!)

Scientific contributions in brief

- Kirchhoff’s Law (Thermodynamics)
- Kirchhoff’s Circuit Laws
- Spectroscopy (with Bunsen)
- Fresnel-Kirchhoff diffraction formula.

Kirchhoff’s Law (Thermodynamics)

- At thermal equilibrium, light emitted equals light absorbed.
- (Otherwise it wouldn’t be at equilibrium.)
- So, black bodies are great emitters.
- And “Space Blankets” are good at not emitting.

Kirchhoff’s Circuit Laws

- The Sum of voltage rises and drops around a loop equals zero.
- (Energy is conserved.)
- Currents entering a junction are equal to currents leaving a junction.
- (Charge is conserved, similar to thermodynamic law. Remember, a lot of people thought charge was like heat, and might accumulate at a junction.)
- So, we can do circuit analysis.
- Obvious, but useful – maybe we can all get laws named after us someday!

Spectroscopy

“Two old telescopes, a prism, and a cigar box”

A Great Spectroscopy Experiment

- Burned highly purified sodium, observed two strong yellow lines
- Lit a Drummond light, which is a stick of lime heated by a flame to white hot – it radiates nearly as a black body, with no dark lines
- Lit a sodium flame in between the “limelight” and the spectroscope, and observed two dark lines – the sodium absorbed more energy than it emitted

Spectroscopy results

- Identified Fraunhofer’s yellow lines in several lamp spectra as sodium emission
- Identified Fraunhofer’s dark lines in the solar spectrum as absorption
- Identified the chemical content of the sun
- Identified Cesium and Rubidium

Fresnel-Kirchhoff diffraction formula.

- Fresnel derived a formula for diffraction by applying Newton’s calculus to Huygen’s wavelets.
- In 1887, Kirchhoff used Maxwell’s Equations to justify Fresnel’s formula.
- Hence, it was named after both Fresnel and Kirchhoff.
- Apparently, it killed him, as he died that year.

References

- http://en.wikipedia.org/wiki/Gustav_Kirchhoff
- www.familysearch.org
- http://dbhs.wvusd.k12.ca.us/webdocs/Chem-History/Kirchhoff-Bunsen-1860.html
- http://www.neatherd.org/astronomy/Fingerprints%20of%20light.htm
- http://optics.byu.edu/Textbook.htm

Download Presentation

Connecting to Server..