Diagram of a Lummer-Brodhun tively, falls on a diffuse white photometer head. surface W. Some of the light which is scattered bythis surface is reflected from the . The Lummer Brodhun Photometer finds wide application in comparison of illuminating power of different light sources. Our L.B. Photometer design and selection. 2 PRINCIPLES OF PHOTOMETRY. 3 LUMMER – BRODHUN PHOTOMETER. 4 PROBLEMS. PH UNIT- 3 LECT – 1. UNIT III LECT – 1. 2. PHOTOMETRY.

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On either side of the screen are two large circular apertures in the sides of the box.

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Where they do, all the light is transmitted to the other side. This item is a Lummer-Brodhun Photometer. April 1, Published: Not Accessible Your account may give you access. The housing is attached to a yoke on which it pivots. Cited by links are available to subscribers only. The housing has no mechanism for adjusting the mirrors and is plain on the outside. This cube directs the light rays coming from both sides of the disk into the eyepiece so that the brdhun can observe the light from both sources simultaneously.

Lummer Brodhun Photometer | NISCO

Light from each of the two sources enters through its respective entrance and illuminates one side of the white disk. By continuing to use this site, you agree to our use of cookies. By moving the unknown light source farther or closer to the photometer, one tries to get rid of the two photommeter circles. In the box above the screen are two mirrors and a pair of prisms, which direct the light from the two light sources outside the box into the eyepiece at lumjer top of the box.

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Journal of the Optical Society of America. Equipment puotometer Class Rooms. When this is accomplished, the luminosity of the unknown source can be calculated.

Similar to the Weber Photometer this item was designed to compare the brightness of an unknown light source to the brightness of a standard light source.

By matching the brightnesses of the two, the observer can use the known luminosity of one source and the distances to both sources to calculate the luminosity of the unknown source.

For a fuller description, see the following website.

You may subscribe either as an OSA member, or as an authorized user of your institution. The light that is reflected off each side of the disk is directed through a right angled prism and towards a Lummer-Brodhun cube. Click here to see what’s new. Function This instrument was used in comparing the brightness of an unknown source of light with that of a standard one. Where the prisms do not touch, total internal reflection occurs. The observer can then see a circular disc of light from one source, surrounded by an halo from the other.


The yoke is attached to a brass rod for insertion into an optical bench or other equipment.

Journal of the Optical Society of America

Sc Practical Physics, pg OSA will be closed for the holidays from 21 December A Lummer-Brodhun cube is made up of two brodhjn prisms that are placed with their hypotenuse sides together to form a cube. Right click equation to reveal menu options. Cited By You do not have subscription access to ulmmer journal. This Photometer consists of a metal box with two entrances and an eyepiece as well as a slot which allows a white magnesium carbonate disk to be mounted between the two entrances.

The photometer consists of an opaque screen which can be removed from a box. Abstract No abstract available.

Remember me on this computer. What the observer sees in the eyepiece is two superimposed circles on top of each other, one smaller than the other. This website uses cookies to deliver some of our products and services as well as for analytics and to provide you a more personalized experience. Please login to set citation alerts.

When the brightness are identical, the two circles become one. They first strike a white slab. If you require urgent assistance, please contact Customer Service. Equations displayed with MathJax.