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.
|Published (Last):||20 July 2004|
|PDF File Size:||3.52 Mb|
|ePub File Size:||18.79 Mb|
|Price:||Free* [*Free Regsitration Required]|
This item is a Lummer-Brodhun Photometer. Some of the brodhunn light on each side is reflected by mirrors towards what is called a Lummer-Brodhun cube, which consists of two right-angled prisms. The housing is attached to a yoke on which it pivots. 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.
A Lummer-Brodhun cube is made up of two right-angled prisms that are placed with their hypotenuse sides together to form a cube. Sc Practical Physics, pg Privacy Phtoometer of Use.
On either side of lummdr screen are two large circular apertures in the sides of the box.
Similar to the Weber Photometer this item was designed to compare the brightness of an unknown phootmeter source to the brightness of a standard light source. When the brightness are identical, the two circles become one. Figure files are available to subscribers only. If you require urgent assistance, please contact Customer Service.
The light that is reflected off each side of the disk is directed through a right angled prism and towards a Lummer-Brodhun cube. You may subscribe either as an OSA member, or as an authorized user of your institution. Equipment of Class Rooms.
Journal of the Optical Society of America. Light from each brodhum the two sources enters through its respective entrance and illuminates one side of the white disk. The observer can then see a circular disc of light from one source, surrounded by an halo from the other.
OSA will be closed for the holidays from 21 December Right click equation to reveal menu options. Citation lists with outbound citation links are available to subscribers only.
Cited By You do not have subscription access to this rbodhun. Not Accessible Your account may give you access. Remember me on this computer. They first strike a white slab. The Precision of Photometric Measurements F.
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 the top of the box.
Function This instrument was used in comparing the brightness of an unknown source of light with that of a standard one.
Login or Create Account. The housing has no mechanism for adjusting the mirrors and is plain on the outside. Journal of the Optical Society of America Vol.
April 1, Published: For a fuller description, see the following website. 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. Figures 3 You do not have subscription access to this journal. The photometer consists of an opaque screen which can be removed from a box.