Search results
Results from the WOW.Com Content Network
sr is the unit, steradian, sr = rad 2. Because the surface area A of a sphere is 4πr 2, the definition implies that a sphere subtends 4π steradians (≈ 12.56637 sr) at its centre, or that a steradian subtends 1/4π ≈ 0.07958 of a sphere. By the same argument, the maximum solid angle that can be subtended at any point is 4π sr.
Diagram showing a section through the centre of a cone (1) subtending a solid angle of 1 steradian in a sphere of radius r, along with the spherical "cap" (2). The external surface area A of the cap equals r2 only if solid angle of the cone is exactly 1 steradian. Hence, in this figure θ = A/2 and r = 1.
IBM System/4 Pi, a family of avionics computers; 4Pi microscope, a microscope that uses interference and fluorescence computers; 4×π = 12.56637..., the solid angle of a complete sphere measured in steradians; Hermetic detector (also called a 4π detector)
"It is my honor to present our Nation’s first circulating coins dedicated to celebrating American women and their contributions to American history," U.S. Mint deputy director Ventris C. Gibson ...
Some variances in coin size and weight occurred over time, especially as the value of silver varied. In particular, many silver coins changed in the 1870s. [4] The figures cited in the tables are representative of the series, and are generally the latest, or most common, figures for a given coin type.
Here's How You Can Stop Paying Interest on Your Credit Card for a Full Year. ... 4 Lesser-Known Coins That Are Worth Thousands of Dollars. Show comments. Advertisement. Advertisement. In Other News.
Diagram showing a section through the centre of a cone (1) subtending a solid angle of 1 steradian in a sphere of radius r, along with the spherical "cap" (2). The fact that the external surface of the cap has an area of r 2 is shown. Note that this applies only if the solid angle of the cone is exactly 1 steradian. Date: 30 September 2007: Source
A ceramic pot turned into a jackpot for a woman on a walk in the Kutnohorsk Region of the Czech Republic. While out on a stroll, the woman happened upon a roughly 900-year-old stash of more than ...