barcode scanner in asp.net web application Luminous flux P in Objective-C

Drawer QR Code in Objective-C Luminous flux P

Luminous flux P
Recognize QR Code ISO/IEC18004 In Objective-C
Using Barcode Control SDK for iPhone Control to generate, create, read, scan barcode image in iPhone applications.
QR Generation In Objective-C
Using Barcode generator for iPhone Control to generate, create QR image in iPhone applications.
1750 Im
QR Reader In Objective-C
Using Barcode decoder for iPhone Control to read, scan read, scan image in iPhone applications.
Encoding Barcode In Objective-C
Using Barcode maker for iPhone Control to generate, create bar code image in iPhone applications.
Illuminance E1
Drawing QR Code JIS X 0510 In C#
Using Barcode maker for .NET framework Control to generate, create QR Code 2d barcode image in .NET applications.
QR Code ISO/IEC18004 Maker In .NET Framework
Using Barcode encoder for ASP.NET Control to generate, create Quick Response Code image in ASP.NET applications.
1750 lx 4
Printing QR Code JIS X 0510 In Visual Studio .NET
Using Barcode maker for VS .NET Control to generate, create QR Code image in Visual Studio .NET applications.
Painting QR Code ISO/IEC18004 In VB.NET
Using Barcode printer for .NET Control to generate, create QR Code image in VS .NET applications.
Section 161 Illumination
Bar Code Creation In Objective-C
Using Barcode creation for iPhone Control to generate, create bar code image in iPhone applications.
Bar Code Drawer In Objective-C
Using Barcode creator for iPhone Control to generate, create barcode image in iPhone applications.
(l)Andrew McKim/Masterfile, (m)(r)Laura Sifferlin
Painting GS1-128 In Objective-C
Using Barcode creator for iPhone Control to generate, create EAN 128 image in iPhone applications.
Generate UCC - 12 In Objective-C
Using Barcode creator for iPhone Control to generate, create UPCA image in iPhone applications.
Figure 16-5 The illuminance, E, produced by a point source of light varies inversely as the square of the distance from the light source
EAN-8 Drawer In Objective-C
Using Barcode creator for iPhone Control to generate, create EAN-8 Supplement 2 Add-On image in iPhone applications.
Reading Code 3 Of 9 In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
r r 1m E1
Scanning Code 128B In VB.NET
Using Barcode scanner for .NET Control to read, scan read, scan image in VS .NET applications.
Create Code 128 Code Set B In .NET Framework
Using Barcode creator for ASP.NET Control to generate, create Code 128A image in ASP.NET applications.
1 E 9 1
Code39 Creation In None
Using Barcode drawer for Font Control to generate, create Code 39 image in Font applications.
Decoding Data Matrix In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
2m r 3m
Making UPCA In None
Using Barcode creation for Microsoft Word Control to generate, create UPC-A Supplement 2 image in Office Word applications.
Draw UPC-A Supplement 2 In Visual C#.NET
Using Barcode maker for VS .NET Control to generate, create Universal Product Code version A image in Visual Studio .NET applications.
1 E 4 1
An inverse-square relationship What would happen if the sphere surrounding the lamp were larger If the sphere had a radius of 200 m, the luminous flux still would total 1750 lm, but the area of the sphere would be 4 (200 m)2 160 m2, four times larger than the 100-m sphere, as shown in Figure 16-5 The illuminance of the inside of the 200-m sphere is 1750 lm/(160 m2) 348 lx, so 348 lm strikes each square meter The illuminance on the inside surface of the 200-m sphere is one-fourth the illuminance on the inside of the 100-m sphere In the same way, the inside of a sphere with a 300-m radius has an illuminance only (1/3)2, or 1/9, as large as the 100-m sphere Figure 16-5 shows that the illuminance produced by a point source is proportional to 1/r 2, an inverse-square relationship As the light rays spread out in straight lines in all directions from a point source, the number of light rays available to illuminate a unit of area decreases as the square of the distance from the point source Luminous intensity Some luminous sources are specified in candela, cd A candela is not a measure of luminous flux, but of luminous intensity The luminous intensity of a point source is the luminous flux that falls on 1 m2 of the inside of a 1-m-radius sphere Thus, luminous intensity is luminous flux divided by 4 A bulb with 1750 lm of flux has an intensity of 1750 lm/4 139 cd In Figure 16-6, the lightbulb is twice as far away from the screen as the candle For the lightbulb to provide the same illuminance on the lightbulb side of the screen as the candle does on the candle side of the screen, the lightbulb would have to be four times brighter than the candle, and, therefore, the luminous intensity of the lightbulb would have to be four times the luminous intensity of the candle
Figure 16-6 The illuminance is the same on both sides of the screen, though the lightbulb is brighter than the candle
Lamp
Screen
Candle
16 Fundamentals of Light
How to Illuminate a Surface
How would you increase the illuminance of your desktop You could use a brighter bulb, which would increase the luminous flux, or you could move the light source closer to the surface of your desk, thereby decreasing the distance between the light source and the surface it is illuminating To make the problem easier, you can use the simplification that the light source is a point source Thus, the illuminance and distance will follow the inverse-square relationship The problem is further simplified if you assume that light from the source strikes perpendicular to the surface of the desk Using these simplifications, the illuminance caused by a point light source is represented by the following equation Point Source Illuminance E
P 4 r2
Illuminated Minds When deciding how to achieve the correct illuminance on students desktops, architects must consider the luminous flux of the lights as well as the distance of the lights above the desktops In addition, the efficiencies of the light sources are an important economic factor
If an object is illuminated by a point source of light, then the illuminance at the object is equal to the luminous flux of the light source, divided by the surface area of the sphere, whose radius is equal to the distance the object is from the light source
Remember that the luminous flux of the light source is spreading out spherically in all directions, so only a fraction of the luminous flux is available to illuminate the desk Use of this equation is valid only if the light from the luminous source strikes perpendicular to the surface it is illuminating It is also only valid for luminous sources that are small enough or far enough away to be considered point sources Thus, the equation does not give accurate values of illuminance for long, fluorescent lamps or incandescent lightbulbs that are close to the surfaces that they illuminate
Copyright © OnBarcode.com . All rights reserved.