Hello

Welcome lekule blog

Hi, I`m Sostenes, Electrical Technician and PLC`S Programmer.
Everyday I`m exploring the world of Electrical to find better solution for Automation.
together in the world. #lekule86
Join us on

Radiant Flux and Luminous Flux

The electromagnetic radiation with the wavelength from 100 nm and 1 mm is referred as the optical range of radiation. Inside this range, the electromagnetic radiation with wavelength 380 nm to 780 nm is called light and this range is the visible range of wavelength. The optical radiation with wavelengths shorter than 380 nm is called ultraviolet radiation similarly, the optical radiation with wavelength more than 780 nm is called infrared radiation. It is also to be noted that most of the power from a radiation source radiated within optical range of wavelength. Although as per "theory of black body radiation" power is radiated at all wavelengths (from zero to infinity) but it is found that amount of power radiated for the wavelengths other than that in optical range is negligible. As the entire amount of power is radiated in the optical range of wavelengths, it can be said that a 100 W incandescent lamp would radiate 100 W power. From any radiation source, the radiated energy per unit time is referred as the radiant flux. Suppose this radiated energy is denoted as Q joule then

 

Where, Φ is the radiated energy per second and its unit is watt. That means radiant flux is nothing but radiated power.


Although it has already been considered that entire power or flux is radiated within optical range of wavelength but the radiant flux is not equal for all the wavelength. It varies with wavelength. Let us consider Φλ(λ) is radiant flux at wavelength λ. Hence for entire optical range of wavelength the radiant flux will be

 

Now if this radiation is within human visual sensation then this radiant flux is called luminous flux. Luminous flux has a unit i.e. Lumen (lm) instead of watt. The visible range of wavelengths is quite narrow compared to the optical range and sensitivity of human eyes varies considerably with the wavelength within this visible range. The sensitivity of human eyes to the different wavelengths of light can be represented by spectral sensitivity function or luminous efficacy function Vλ. This is actually proportional to relative spectral sensitivity function V(λ). The sensitivity of human eyes in photopic vision is maximum at wavelength 555 nm. The relative spectral sensitivity at that wavelength is taken as 1. The luminous efficacy at the wavelength of 555 nm is 683 lumens/watt. Hence, luminous efficacy at any wavelength within visible range can be found from the equation



Where vλ is relative spectral sensitivity at wavelength λ that means it is the value of relative spectral sensitivity function V(λ) at wavelength λ. Here, Vλ lumens is correlated to one-watt radiant flux at wavelength λ so at Φλ watts radiant flux, there will be ΦλVλ lumens. This quantity is defined as luminous flux at wavelength λ. For entire visible range of wavelength, the luminous flux will be

 

This is the conversion equation that is used to quantify any photometric quantity from the radiometric quantity and we use the equation when we try to correlate the radiant flux and the luminous flux. We can represent the spectral efficacy in the graph of the perceived optical stimulus vs. the incident radiant power as a function of wavelength. The human eye is almost 2.5 times as sensitive at the wavelength of maximum sensitivity when it is dark. photometric function

Share this:

ABOUTME

Hi all. This is deepak from Bthemez. We're providing content for Bold site and we’ve been in internet, social media and affiliate for too long time and its my profession. We are web designer & developer living India! What can I say, we are the best..

Post a Comment
My photo

Hi, I`m Sostenes, Electrical Technician and PLC`S Programmer.
Everyday I`m exploring the world of Electrical to find better solution for Automation. I believe everyday can become a Electrician with the right learning materials.
My goal with BLOG is to help you learn Electrical.

Labels

LEKULE TV EDITORIALS ARTICLES DC ROBOTICS DIGITAL SEMICONDUCTORS GENERATOR AC EXPERIMENTS MANUFACTURING-ENGINEERING REFERENCE FUNDAMENTAL OF ELECTRICITY ELECTRONICS ELECTRICAL ENGINEER MEASUREMENT TRANSDUCER & SENSOR VIDEO ARDUINO RENEWABLE ENERGY AUTOMOBILE TEARDOWN SYNCHRONOUS GENERATOR DIGITAL ELECTRONICS ELECTRICAL DISTRIBUTION CABLES AUTOMOTIVE MICROCONTROLLER SOLAR PROTECTION DIODE AND CIRCUITS BASIC ELECTRICAL ELECTRONICS MOTOR SWITCHES CIRCUIT BREAKERS CIRCUITS THEORY PANEL BUILDING ELECTRONICS DEVICES MIRACLES SWITCHGEAR ANALOG MOBILE DEVICES WEARABLES CAMERA TECHNOLOGY COMMUNICATION GENERATION BATTERIES FREE CIRCUITS INDUSTRIAL AUTOMATION SPECIAL MACHINES ELECTRICAL SAFETY ENERGY EFFIDIENCY-BUILDING DRONE CONTROL SYSTEM NUCLEAR ENERGY SMATRPHONE FILTER`S POWER BIOGAS BELT CONVEYOR MATERIAL HANDLING RELAY ELECTRICAL INSTRUMENTS ENERGY SOURCE PLC`S TRANSFORMER AC CIRCUITS CIRCUIT SCHEMATIC SYMBOLS DDISCRETE SEMICONDUCTOR CIRCUITS WIND POWER C.B DEVICES DC CIRCUITS DIODES AND RECTIFIERS FUSE SPECIAL TRANSFORMER THERMAL POWER PLANT CELL CHEMISTRY EARTHING SYSTEM ELECTRIC LAMP FUNDAMENTAL OF ELECTRICITY 2 BIPOLAR JUNCTION TRANSISTOR 555 TIMER CIRCUITS AUTOCAD BLUETOOTH C PROGRAMMING HOME AUTOMATION HYDRO POWER LOGIC GATES OPERATIONAL AMPLIFIER`S SOLID-STATE DEVICE THEORRY COMPUTER DEFECE & MILITARY FLUORESCENT LAMP INDUSTRIAL ROBOTICS ANDROID ELECTRICAL DRIVES GROUNDING SYSTEM CALCULUS REFERENCE DC METERING CIRCUITS DC NETWORK ANALYSIS ELECTRICAL SAFETY TIPS ELECTRICIAN SCHOOL ELECTRON TUBES FUNDAMENTAL OF ELECTRICITY 1 INDUCTION MACHINES INSULATIONS USB ALGEBRA REFERENCE HMI[Human Interface Machines] INDUCTION MOTOR KARNAUGH MAPPING USEUL EQUIATIONS AND CONVERSION FACTOR ANALOG INTEGRATED CIRCUITS BASIC CONCEPTS AND TEST EQUIPMENTS DIGITAL COMMUNICATION DIGITAL-ANALOG CONVERSION ELECTRICAL SOFTWARE GAS TURBINE ILLUMINATION OHM`S LAW POWER ELECTRONICS THYRISTOR BOOLEAN ALGEBRA DIGITAL INTEGRATED CIRCUITS FUNDAMENTAL OF ELECTRICITY 3 PHYSICS OF CONDUCTORS AND INSULATORS SPECIAL MOTOR STEAM POWER PLANTS TESTING TRANSMISION LINE C-BISCUIT CAPACITORS COMBINATION LOGIC FUNCTION COMPLEX NUMBERS CONTROL MOTION ELECTRICAL LAWS INVERTER LADDER DIAGRAM MULTIVIBRATORS RC AND L/R TIME CONSTANTS SCADA SERIES AND PARALLEL CIRCUITS USING THE SPICE CIRCUIT SIMULATION PROGRAM AMPLIFIERS AND ACTIVE DEVICES APPS & SOFTWARE BASIC CONCEPTS OF ELECTRICITY CONDUCTOR AND INSULATORS TABLES CONDUITS FITTING AND SUPPORTS ELECTRICAL INSTRUMENTATION SIGNALS ELECTRICAL TOOLS INDUCTORS LiDAR MAGNETISM AND ELECTROMAGNETISM PLYPHASE AC CIRCUITS RECLOSER SAFE LIVING WITH GAS AND LPG SAFETY CLOTHING STEPPER MOTOR SYNCHRONOUS MOTOR AC METRING CIRCUITS BECOME AN ELECTRICIAN BINARY ARITHMETIC BUSHING DIGITAL STORAGE MEMROY ELECTRICIAN JOBS HEAT ENGINES HOME THEATER INPECTIONS LIGHT SABER MOSFET NUMERATION SYSTEM POWER FACTORS REACTANCE AND IMPEDANCE INDUCTIVE RECTIFIER AND CONVERTERS RESONANCE SCIENTIFIC NOTATION AND METRIC PREFIXES SULFURIC ACID TROUBLESHOOTING TROUBLESHOOTING-THEORY & PRACTICE 12C BUS APPLE BATTERIES AND POWER SYSTEMS DC MOTOR DRIVES ELECTROMECHANICAL RELAYS ENERGY EFFICIENCY-LIGHT INDUSTRIAL SAFETY EQUIPMENTS MEGGER MXED-FREQUENCY AC SIGNALS PRINCIPLE OF DIGITAL COMPUTING QUESTIONS REACTANCE AND IMPEDANCE-CAPATIVE SEQUENTIAL CIRCUITS SERRIES-PARALLEL COMBINATION CIRCUITS SHIFT REGISTERS WIRELESS BUILDING SERVICES COMPRESSOR CRANES DIVIDER CIRCUIT AND KIRCHHOFF`S LAW ELECTRICAL DISTRIBUTION EQUIPMENTS 1 ELECTRICAL DISTRIBUTION EQUIPMENTS B ELECTRICAL TOOL KIT ELECTRICIAN JOB DESCRIPTION INDUSTRIAL DRIVES LAPTOP SCIENCE THERMOCOUPLE TRIGONOMENTRY REFERENCE UART oscilloscope BIOMASS CONTACTOR ELECTRIC ILLUMINATION ELECTRICAL SAFETY TRAINING ELECTROMECHANICAL FEATURED FILTER DESIGN HARDWARE JUNCTION FIELD-EFFECT TRANSISTORS NASA NUCLEAR POWER VALVE COLOR CODES ELECTRIC TRACTION FLEXIBLE ELECTRONICS FLUKE GEARMOTORS INTRODUCTION LASSER PID PUMP SEAL ELECTRICIAN CAREER ELECTRICITY SUPPLY AND DISTRIBUTION MUSIC NEUTRAL PERIODIC TABLES OF THE ELEMENTS POLYPHASE AC CIRCUITS PROJECTS REATORS SATELLITE STAR DELTA VIBRATION WATERPROOF