PHOTOMETRY

6B10.15 INVERSE SQUARE MODEL
6B40.10 VARIAC AND LIGHT BULB (BLACKBODY RADIATION)
6B40.20 BLACKBODY MODEL



6B10.15 Inverse Square Law

Demonstrate inverse square law by shining a laser through one of the gratings from the glasses we have for students to use to view emission spectra.

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Setup Requirements: Minimal

 

Equations: Area of squares varies with distance squared.

 

Safety Issues: Laser



6B40.10 Variac and Light Bulb

Demonstrate how brightness and color of light varies with temperature.

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Setup Requirements: Minimal

 

Equations: Brightness proportional to 4th power of temperature. Wavelength of peak color proportional to 1/T.

 

Safety Issues: Hot light bulb, AC line voltage present



6B40.20 Blackbody Model

A box is painted black on the outside and painted white on the inside. Take cover off to show white inside and show 1" hole. Replace cover and show 1" hole is black. Light entering through hole is scattered so little comes back out. Thus if you see a color inside it is probably due to light source inside being hot enough to produce visible light. Show with light such as flashlight inside.

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Setup Requirements: Off the shelf

Equations: Planck's Blackbody Equation

Safety Issues: None