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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The photometer consists of an opaque screen which can be removed from a box. Where the prisms do not touch, total internal reflection occurs. The housing has no mechanism for adjusting the mirrors and is plain on the outside.

File:Photomètre Lummer-Brodhun.png

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. This cube directs the light rays coming from both sides of the disk into the eyepiece so that the user can observe the light from both sources simultaneously.

Abstract No abstract available. Figure files are available to subscribers only. The housing is attached to a yoke on which it pivots.

This item is a Lummer-Brodhun Photometer. Where they do, all the light is transmitted to the other side. Cited by links are available to subscribers only. They first strike a white slab. By continuing to use this site, you agree to our use of cookies.


Light from each of the two sources enters through its respective entrance and illuminates one side of the white disk. Click here to see what’s new. Cited By You do not have subscription access to this journal. You do not have subscription access to this journal.

Login or Create Account. When the brightness are identical, the two circles become one.

Lummer Brodhun Photometer

Light rays from the two sources enter on either side of the box. Journal of the Optical Society of America.

Journal of the Optical Society of America Vol. The observer can then see a circular disc photomrter light from one source, surrounded by lunmer halo from the other. Figures 3 You do not have subscription access to this journal. Click here to learn more. Some of the scattered light on each side is reflected by mirrors towards what is called a Lummer-Brodhun cube, which consists of two right-angled prisms.

Password Forgot your password? If you require urgent assistance, please contact Customer Service. This website uses cookies to deliver some of our products and phootmeter as well as for analytics and to provide you a more personalized experience. The yoke is attached to a brass rod for insertion into an optical bench or other equipment. We’ve also updated our Privacy Notice.

OSA | A New Principle and its Application to the Lummer-Brodhun Photometer

,ummer For a fuller description, see the following website. Citation lists with outbound citation links are available to subscribers only. References You do not have subscription access to this journal.


Equations displayed with MathJax. The light that is reflected off each side of the disk is directed through a right angled prism and towards a Lummer-Brodhun cube. 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 photomeeter luminosity of the unknown source. On either side of the screen are two large circular apertures in the sides of the box. A Lummer-Brodhun cube is made up of two right-angled prisms that are placed with their hypotenuse sides together to form a cube. Privacy Terms of Use. What the observer sees in the eyepiece is two superimposed circles on top of each other, one smaller than the other.

OSA will be closed for the holidays from 21 December Please login to set citation alerts. When this is accomplished, the luminosity of the unknown source can be calculated.

Remember me on this computer. Sc Practical Physics, pg

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