SlideShare a Scribd company logo
Blackbody
Hot blackbody emissions
A blackbody is a rigid, closed
unreal body that can absorb all
electromagnetic radiation that
falls on it regardless of its
frequencies, but it reflects
none.
It is a perfect
emitter and
absorber of
thermal
radiations
following
Kirchhoff's law.
On heating, the blackbody releases all thermal
electromagnetic radiation that it absorbed
previously. These are blackbody radiations. A
blackbody radiates heat energies without affecting
the intervening medium. It has the highest emissive
power of all other bodies at that particular
temperature and wavelength conditions.
An ideal black body is an imaginary
perception of Gustav Kirchhoff.
The blackbody is inexistent.
An object with above 0.95
emissivities is an
approximate blackbody.
A graph between emissive power
and radiation wavelength at a
fixed temperature T is known as a
blackbody curve. At different
source temperatures, we observe
different black body curves.
Blog:https://jayamchemistrylearners.blogspot.com/
The black body spectrum depends only
on the temperature. And it is
independent of the shape, structure, and
composition of blackbody enclosure.
Factors affecting
blackbody emission
Temperature
Emissivity
Surface area
Laws governing
blackbody emission
Planck quantum law
Wien displacement law
Stefan-Boltzmann law

More Related Content

Similar to Blackbody radiations infographic.pdf

Physics - Heat transfer, Radiation
Physics - Heat transfer, RadiationPhysics - Heat transfer, Radiation
Physics - Heat transfer, Radiation
Abhishek Chaudhary
 
Black Body Radiation
Black Body RadiationBlack Body Radiation
Black Body Radiation
M.G. College, Armori
 
Module 3 Engg Phys.pptx
Module 3 Engg Phys.pptxModule 3 Engg Phys.pptx
Module 3 Engg Phys.pptx
udaykumar171189
 
Laws of readiation
Laws of readiationLaws of readiation
Laws of readiation
9601865455
 
Modern physics
Modern physicsModern physics
Modern physics
Anupom Ghosh Antor
 
Plank’s Quantum theory.pptx
Plank’s Quantum theory.pptxPlank’s Quantum theory.pptx
Plank’s Quantum theory.pptx
RakeshKhetrapal1
 
RAHIDUL SEKH--60(BLACK-BODY RADIATION0.pptx
RAHIDUL SEKH--60(BLACK-BODY RADIATION0.pptxRAHIDUL SEKH--60(BLACK-BODY RADIATION0.pptx
RAHIDUL SEKH--60(BLACK-BODY RADIATION0.pptx
rahidulbcet
 
Blackbody radiation
Blackbody radiationBlackbody radiation
Blackbody radiation
NobleMon1
 
Chapter 1 blackbody radiation
Chapter 1  blackbody radiationChapter 1  blackbody radiation
Chapter 1 blackbody radiationMiza Kamaruzzaman
 
Chapter 1 blackbody radiation
Chapter 1  blackbody radiationChapter 1  blackbody radiation
Chapter 1 blackbody radiationMiza Kamaruzzaman
 
Concept of Grey body and Black body
Concept of Grey body and Black bodyConcept of Grey body and Black body
Concept of Grey body and Black body
PranavkumarRana
 
Radiation heat transfer
Radiation heat transferRadiation heat transfer
Radiation heat transfer
Aravind Sp
 
Relation between a small body in a large enclosure
Relation between a small body in a large enclosureRelation between a small body in a large enclosure
Relation between a small body in a large enclosure
Sharath Kumar
 
Laws of radiation
Laws of radiationLaws of radiation
Laws of radiation
Meet2395
 
Fundamentals of thermal radiations
Fundamentals of thermal radiationsFundamentals of thermal radiations
Fundamentals of thermal radiations
Ihsan Wassan
 
Radiation and its properties
Radiation and its propertiesRadiation and its properties
Radiation and its properties
GLA UNIVERSITY MATHURA
 
Radiation
Radiation Radiation
Radiation
green mechanics
 
Radiation
RadiationRadiation
radiation laws
radiation lawsradiation laws
radiation laws
HimanjaliMHA
 

Similar to Blackbody radiations infographic.pdf (20)

Physics - Heat transfer, Radiation
Physics - Heat transfer, RadiationPhysics - Heat transfer, Radiation
Physics - Heat transfer, Radiation
 
Black Body Radiation
Black Body RadiationBlack Body Radiation
Black Body Radiation
 
radiasi benda hitam
radiasi benda hitamradiasi benda hitam
radiasi benda hitam
 
Module 3 Engg Phys.pptx
Module 3 Engg Phys.pptxModule 3 Engg Phys.pptx
Module 3 Engg Phys.pptx
 
Laws of readiation
Laws of readiationLaws of readiation
Laws of readiation
 
Modern physics
Modern physicsModern physics
Modern physics
 
Plank’s Quantum theory.pptx
Plank’s Quantum theory.pptxPlank’s Quantum theory.pptx
Plank’s Quantum theory.pptx
 
RAHIDUL SEKH--60(BLACK-BODY RADIATION0.pptx
RAHIDUL SEKH--60(BLACK-BODY RADIATION0.pptxRAHIDUL SEKH--60(BLACK-BODY RADIATION0.pptx
RAHIDUL SEKH--60(BLACK-BODY RADIATION0.pptx
 
Blackbody radiation
Blackbody radiationBlackbody radiation
Blackbody radiation
 
Chapter 1 blackbody radiation
Chapter 1  blackbody radiationChapter 1  blackbody radiation
Chapter 1 blackbody radiation
 
Chapter 1 blackbody radiation
Chapter 1  blackbody radiationChapter 1  blackbody radiation
Chapter 1 blackbody radiation
 
Concept of Grey body and Black body
Concept of Grey body and Black bodyConcept of Grey body and Black body
Concept of Grey body and Black body
 
Radiation heat transfer
Radiation heat transferRadiation heat transfer
Radiation heat transfer
 
Relation between a small body in a large enclosure
Relation between a small body in a large enclosureRelation between a small body in a large enclosure
Relation between a small body in a large enclosure
 
Laws of radiation
Laws of radiationLaws of radiation
Laws of radiation
 
Fundamentals of thermal radiations
Fundamentals of thermal radiationsFundamentals of thermal radiations
Fundamentals of thermal radiations
 
Radiation and its properties
Radiation and its propertiesRadiation and its properties
Radiation and its properties
 
Radiation
Radiation Radiation
Radiation
 
Radiation
RadiationRadiation
Radiation
 
radiation laws
radiation lawsradiation laws
radiation laws
 

More from SaiKalyani11

de-Broglie equation.pdf
de-Broglie equation.pdfde-Broglie equation.pdf
de-Broglie equation.pdf
SaiKalyani11
 
Wien displacement law graph.pdf
Wien displacement law graph.pdfWien displacement law graph.pdf
Wien displacement law graph.pdf
SaiKalyani11
 
MCQs of blackbody & its radiation .pdf
MCQs of blackbody & its radiation .pdfMCQs of blackbody & its radiation .pdf
MCQs of blackbody & its radiation .pdf
SaiKalyani11
 
Fatafat check list of blackbody.pdf
Fatafat check list of blackbody.pdfFatafat check list of blackbody.pdf
Fatafat check list of blackbody.pdf
SaiKalyani11
 
Wien displacement law .pdf
Wien displacement law .pdfWien displacement law .pdf
Wien displacement law .pdf
SaiKalyani11
 
Blackbody Vs. graybody.pdf
Blackbody Vs. graybody.pdfBlackbody Vs. graybody.pdf
Blackbody Vs. graybody.pdf
SaiKalyani11
 
MCQs of blackbody & Kirchhoff's law.pdf
MCQs of blackbody & Kirchhoff's law.pdfMCQs of blackbody & Kirchhoff's law.pdf
MCQs of blackbody & Kirchhoff's law.pdf
SaiKalyani11
 
Planck quantum theory.pdf
Planck quantum theory.pdfPlanck quantum theory.pdf
Planck quantum theory.pdf
SaiKalyani11
 
Kirchhoff's law formula and its derivation. Numerical problems.pdf
Kirchhoff's law formula and its derivation. Numerical problems.pdfKirchhoff's law formula and its derivation. Numerical problems.pdf
Kirchhoff's law formula and its derivation. Numerical problems.pdf
SaiKalyani11
 
Planck's constant.pdf
Planck's constant.pdfPlanck's constant.pdf
Planck's constant.pdf
SaiKalyani11
 
Numerical problems of Planck's quantum theory.pdf
Numerical problems of Planck's quantum theory.pdfNumerical problems of Planck's quantum theory.pdf
Numerical problems of Planck's quantum theory.pdf
SaiKalyani11
 
MCQ on Planck constant.pdf
MCQ on Planck constant.pdfMCQ on Planck constant.pdf
MCQ on Planck constant.pdf
SaiKalyani11
 
Detailed light theories.pdf
Detailed light theories.pdfDetailed light theories.pdf
Detailed light theories.pdf
SaiKalyani11
 
Theories of light.pdf
Theories of light.pdfTheories of light.pdf
Theories of light.pdf
SaiKalyani11
 
MCQ's on hydrogen spectrum.pdf
MCQ's on hydrogen spectrum.pdfMCQ's on hydrogen spectrum.pdf
MCQ's on hydrogen spectrum.pdf
SaiKalyani11
 
Rydberg equation.pdf
Rydberg equation.pdfRydberg equation.pdf
Rydberg equation.pdf
SaiKalyani11
 
Some important points of Rydberg formula.pdf
Some important points of Rydberg formula.pdfSome important points of Rydberg formula.pdf
Some important points of Rydberg formula.pdf
SaiKalyani11
 
The applications of spectral studies.pdf
The applications of spectral studies.pdfThe applications of spectral studies.pdf
The applications of spectral studies.pdf
SaiKalyani11
 
Rydberg-Ritz combination principle.pdf
Rydberg-Ritz combination principle.pdfRydberg-Ritz combination principle.pdf
Rydberg-Ritz combination principle.pdf
SaiKalyani11
 
Rydberg formula.pdf
Rydberg formula.pdfRydberg formula.pdf
Rydberg formula.pdf
SaiKalyani11
 

More from SaiKalyani11 (20)

de-Broglie equation.pdf
de-Broglie equation.pdfde-Broglie equation.pdf
de-Broglie equation.pdf
 
Wien displacement law graph.pdf
Wien displacement law graph.pdfWien displacement law graph.pdf
Wien displacement law graph.pdf
 
MCQs of blackbody & its radiation .pdf
MCQs of blackbody & its radiation .pdfMCQs of blackbody & its radiation .pdf
MCQs of blackbody & its radiation .pdf
 
Fatafat check list of blackbody.pdf
Fatafat check list of blackbody.pdfFatafat check list of blackbody.pdf
Fatafat check list of blackbody.pdf
 
Wien displacement law .pdf
Wien displacement law .pdfWien displacement law .pdf
Wien displacement law .pdf
 
Blackbody Vs. graybody.pdf
Blackbody Vs. graybody.pdfBlackbody Vs. graybody.pdf
Blackbody Vs. graybody.pdf
 
MCQs of blackbody & Kirchhoff's law.pdf
MCQs of blackbody & Kirchhoff's law.pdfMCQs of blackbody & Kirchhoff's law.pdf
MCQs of blackbody & Kirchhoff's law.pdf
 
Planck quantum theory.pdf
Planck quantum theory.pdfPlanck quantum theory.pdf
Planck quantum theory.pdf
 
Kirchhoff's law formula and its derivation. Numerical problems.pdf
Kirchhoff's law formula and its derivation. Numerical problems.pdfKirchhoff's law formula and its derivation. Numerical problems.pdf
Kirchhoff's law formula and its derivation. Numerical problems.pdf
 
Planck's constant.pdf
Planck's constant.pdfPlanck's constant.pdf
Planck's constant.pdf
 
Numerical problems of Planck's quantum theory.pdf
Numerical problems of Planck's quantum theory.pdfNumerical problems of Planck's quantum theory.pdf
Numerical problems of Planck's quantum theory.pdf
 
MCQ on Planck constant.pdf
MCQ on Planck constant.pdfMCQ on Planck constant.pdf
MCQ on Planck constant.pdf
 
Detailed light theories.pdf
Detailed light theories.pdfDetailed light theories.pdf
Detailed light theories.pdf
 
Theories of light.pdf
Theories of light.pdfTheories of light.pdf
Theories of light.pdf
 
MCQ's on hydrogen spectrum.pdf
MCQ's on hydrogen spectrum.pdfMCQ's on hydrogen spectrum.pdf
MCQ's on hydrogen spectrum.pdf
 
Rydberg equation.pdf
Rydberg equation.pdfRydberg equation.pdf
Rydberg equation.pdf
 
Some important points of Rydberg formula.pdf
Some important points of Rydberg formula.pdfSome important points of Rydberg formula.pdf
Some important points of Rydberg formula.pdf
 
The applications of spectral studies.pdf
The applications of spectral studies.pdfThe applications of spectral studies.pdf
The applications of spectral studies.pdf
 
Rydberg-Ritz combination principle.pdf
Rydberg-Ritz combination principle.pdfRydberg-Ritz combination principle.pdf
Rydberg-Ritz combination principle.pdf
 
Rydberg formula.pdf
Rydberg formula.pdfRydberg formula.pdf
Rydberg formula.pdf
 

Recently uploaded

Language Across the Curriculm LAC B.Ed.
Language Across the  Curriculm LAC B.Ed.Language Across the  Curriculm LAC B.Ed.
Language Across the Curriculm LAC B.Ed.
Atul Kumar Singh
 
1.4 modern child centered education - mahatma gandhi-2.pptx
1.4 modern child centered education - mahatma gandhi-2.pptx1.4 modern child centered education - mahatma gandhi-2.pptx
1.4 modern child centered education - mahatma gandhi-2.pptx
JosvitaDsouza2
 
Biological Screening of Herbal Drugs in detailed.
Biological Screening of Herbal Drugs in detailed.Biological Screening of Herbal Drugs in detailed.
Biological Screening of Herbal Drugs in detailed.
Ashokrao Mane college of Pharmacy Peth-Vadgaon
 
Embracing GenAI - A Strategic Imperative
Embracing GenAI - A Strategic ImperativeEmbracing GenAI - A Strategic Imperative
Embracing GenAI - A Strategic Imperative
Peter Windle
 
Phrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXX
Phrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXXPhrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXX
Phrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXX
MIRIAMSALINAS13
 
special B.ed 2nd year old paper_20240531.pdf
special B.ed 2nd year old paper_20240531.pdfspecial B.ed 2nd year old paper_20240531.pdf
special B.ed 2nd year old paper_20240531.pdf
Special education needs
 
TESDA TM1 REVIEWER FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...
TESDA TM1 REVIEWER  FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...TESDA TM1 REVIEWER  FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...
TESDA TM1 REVIEWER FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...
EugeneSaldivar
 
Operation Blue Star - Saka Neela Tara
Operation Blue Star   -  Saka Neela TaraOperation Blue Star   -  Saka Neela Tara
Operation Blue Star - Saka Neela Tara
Balvir Singh
 
Chapter 3 - Islamic Banking Products and Services.pptx
Chapter 3 - Islamic Banking Products and Services.pptxChapter 3 - Islamic Banking Products and Services.pptx
Chapter 3 - Islamic Banking Products and Services.pptx
Mohd Adib Abd Muin, Senior Lecturer at Universiti Utara Malaysia
 
Palestine last event orientationfvgnh .pptx
Palestine last event orientationfvgnh .pptxPalestine last event orientationfvgnh .pptx
Palestine last event orientationfvgnh .pptx
RaedMohamed3
 
Unit 2- Research Aptitude (UGC NET Paper I).pdf
Unit 2- Research Aptitude (UGC NET Paper I).pdfUnit 2- Research Aptitude (UGC NET Paper I).pdf
Unit 2- Research Aptitude (UGC NET Paper I).pdf
Thiyagu K
 
CACJapan - GROUP Presentation 1- Wk 4.pdf
CACJapan - GROUP Presentation 1- Wk 4.pdfCACJapan - GROUP Presentation 1- Wk 4.pdf
CACJapan - GROUP Presentation 1- Wk 4.pdf
camakaiclarkmusic
 
Guidance_and_Counselling.pdf B.Ed. 4th Semester
Guidance_and_Counselling.pdf B.Ed. 4th SemesterGuidance_and_Counselling.pdf B.Ed. 4th Semester
Guidance_and_Counselling.pdf B.Ed. 4th Semester
Atul Kumar Singh
 
Lapbook sobre os Regimes Totalitários.pdf
Lapbook sobre os Regimes Totalitários.pdfLapbook sobre os Regimes Totalitários.pdf
Lapbook sobre os Regimes Totalitários.pdf
Jean Carlos Nunes Paixão
 
678020731-Sumas-y-Restas-Para-Colorear.pdf
678020731-Sumas-y-Restas-Para-Colorear.pdf678020731-Sumas-y-Restas-Para-Colorear.pdf
678020731-Sumas-y-Restas-Para-Colorear.pdf
CarlosHernanMontoyab2
 
A Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in EducationA Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in Education
Peter Windle
 
Additional Benefits for Employee Website.pdf
Additional Benefits for Employee Website.pdfAdditional Benefits for Employee Website.pdf
Additional Benefits for Employee Website.pdf
joachimlavalley1
 
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdf
Welcome to TechSoup   New Member Orientation and Q&A (May 2024).pdfWelcome to TechSoup   New Member Orientation and Q&A (May 2024).pdf
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdf
TechSoup
 
Supporting (UKRI) OA monographs at Salford.pptx
Supporting (UKRI) OA monographs at Salford.pptxSupporting (UKRI) OA monographs at Salford.pptx
Supporting (UKRI) OA monographs at Salford.pptx
Jisc
 
The Roman Empire A Historical Colossus.pdf
The Roman Empire A Historical Colossus.pdfThe Roman Empire A Historical Colossus.pdf
The Roman Empire A Historical Colossus.pdf
kaushalkr1407
 

Recently uploaded (20)

Language Across the Curriculm LAC B.Ed.
Language Across the  Curriculm LAC B.Ed.Language Across the  Curriculm LAC B.Ed.
Language Across the Curriculm LAC B.Ed.
 
1.4 modern child centered education - mahatma gandhi-2.pptx
1.4 modern child centered education - mahatma gandhi-2.pptx1.4 modern child centered education - mahatma gandhi-2.pptx
1.4 modern child centered education - mahatma gandhi-2.pptx
 
Biological Screening of Herbal Drugs in detailed.
Biological Screening of Herbal Drugs in detailed.Biological Screening of Herbal Drugs in detailed.
Biological Screening of Herbal Drugs in detailed.
 
Embracing GenAI - A Strategic Imperative
Embracing GenAI - A Strategic ImperativeEmbracing GenAI - A Strategic Imperative
Embracing GenAI - A Strategic Imperative
 
Phrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXX
Phrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXXPhrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXX
Phrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXX
 
special B.ed 2nd year old paper_20240531.pdf
special B.ed 2nd year old paper_20240531.pdfspecial B.ed 2nd year old paper_20240531.pdf
special B.ed 2nd year old paper_20240531.pdf
 
TESDA TM1 REVIEWER FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...
TESDA TM1 REVIEWER  FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...TESDA TM1 REVIEWER  FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...
TESDA TM1 REVIEWER FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...
 
Operation Blue Star - Saka Neela Tara
Operation Blue Star   -  Saka Neela TaraOperation Blue Star   -  Saka Neela Tara
Operation Blue Star - Saka Neela Tara
 
Chapter 3 - Islamic Banking Products and Services.pptx
Chapter 3 - Islamic Banking Products and Services.pptxChapter 3 - Islamic Banking Products and Services.pptx
Chapter 3 - Islamic Banking Products and Services.pptx
 
Palestine last event orientationfvgnh .pptx
Palestine last event orientationfvgnh .pptxPalestine last event orientationfvgnh .pptx
Palestine last event orientationfvgnh .pptx
 
Unit 2- Research Aptitude (UGC NET Paper I).pdf
Unit 2- Research Aptitude (UGC NET Paper I).pdfUnit 2- Research Aptitude (UGC NET Paper I).pdf
Unit 2- Research Aptitude (UGC NET Paper I).pdf
 
CACJapan - GROUP Presentation 1- Wk 4.pdf
CACJapan - GROUP Presentation 1- Wk 4.pdfCACJapan - GROUP Presentation 1- Wk 4.pdf
CACJapan - GROUP Presentation 1- Wk 4.pdf
 
Guidance_and_Counselling.pdf B.Ed. 4th Semester
Guidance_and_Counselling.pdf B.Ed. 4th SemesterGuidance_and_Counselling.pdf B.Ed. 4th Semester
Guidance_and_Counselling.pdf B.Ed. 4th Semester
 
Lapbook sobre os Regimes Totalitários.pdf
Lapbook sobre os Regimes Totalitários.pdfLapbook sobre os Regimes Totalitários.pdf
Lapbook sobre os Regimes Totalitários.pdf
 
678020731-Sumas-y-Restas-Para-Colorear.pdf
678020731-Sumas-y-Restas-Para-Colorear.pdf678020731-Sumas-y-Restas-Para-Colorear.pdf
678020731-Sumas-y-Restas-Para-Colorear.pdf
 
A Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in EducationA Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in Education
 
Additional Benefits for Employee Website.pdf
Additional Benefits for Employee Website.pdfAdditional Benefits for Employee Website.pdf
Additional Benefits for Employee Website.pdf
 
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdf
Welcome to TechSoup   New Member Orientation and Q&A (May 2024).pdfWelcome to TechSoup   New Member Orientation and Q&A (May 2024).pdf
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdf
 
Supporting (UKRI) OA monographs at Salford.pptx
Supporting (UKRI) OA monographs at Salford.pptxSupporting (UKRI) OA monographs at Salford.pptx
Supporting (UKRI) OA monographs at Salford.pptx
 
The Roman Empire A Historical Colossus.pdf
The Roman Empire A Historical Colossus.pdfThe Roman Empire A Historical Colossus.pdf
The Roman Empire A Historical Colossus.pdf
 

Blackbody radiations infographic.pdf

  • 1. Blackbody Hot blackbody emissions A blackbody is a rigid, closed unreal body that can absorb all electromagnetic radiation that falls on it regardless of its frequencies, but it reflects none. It is a perfect emitter and absorber of thermal radiations following Kirchhoff's law. On heating, the blackbody releases all thermal electromagnetic radiation that it absorbed previously. These are blackbody radiations. A blackbody radiates heat energies without affecting the intervening medium. It has the highest emissive power of all other bodies at that particular temperature and wavelength conditions. An ideal black body is an imaginary perception of Gustav Kirchhoff. The blackbody is inexistent. An object with above 0.95 emissivities is an approximate blackbody. A graph between emissive power and radiation wavelength at a fixed temperature T is known as a blackbody curve. At different source temperatures, we observe different black body curves. Blog:https://jayamchemistrylearners.blogspot.com/ The black body spectrum depends only on the temperature. And it is independent of the shape, structure, and composition of blackbody enclosure. Factors affecting blackbody emission Temperature Emissivity Surface area Laws governing blackbody emission Planck quantum law Wien displacement law Stefan-Boltzmann law