The Nature of Electromagnetic Radiation

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "The Nature of Electromagnetic Radiation"

Transcription

1 II The Nature of Electromagnetic Radiation The Sun s energy has traveled across space as electromagnetic radiation, and that is the form in which it arrives on Earth. It is this radiation that determines the effect of the Sun s energy on the Earth and its climate. Infrared radiation, radio waves, visible light, and ultraviolet rays are all forms of electromagnetic radiation. One of the best ways to understand the production of this type of energy is to consider how it is emitted by atoms, in particular the hydrogen atom. Energy Levels of Atoms Allowed Energies of the Electron Since before the turn of the century, it has been known that an individual atom is made up of a nucleus (composed of protons and neutrons) and electrons bound to the nucleus, and that the electrons (and hence the atom) have very well defined, discrete amounts of energy. The simplest atom, hydrogen, is composed of a proton (its nucleus) and an electron bound to it by the electrical force of attraction. (Electrons have a negative charge and protons a positive one.) The electron may have only certain values of energy when it is bound to the nucleus in this way. The lowest energy level, in which the electron is closest to the nucleus, is called the ground level. The next level is the first excited level, and so on (see Figure 4). There are various ways the electron may be moved to higher levels, and one of those ways is by receiving energy from electromagnetic radiation. What determines the amount of energy electromagnetic radiation may have? Energy of Electromagnetic Radiation In many situations electromagnetic radiation may be described as having a wave-like nature. Three important features of waves of any sort are the wavelength (the distance between adjacent crests), the frequency (how fast the crests move up and down), and the speed (how fast the crests move forward). There is a basic relationship between these features. If we multiply the wavelength (symbolized by λ, the Greek letter lambda) by the frequency (f), we obtain the speed of the wave, v. The mathematical formula is λf = v When the electromagnetic radiation is moving through space or another vacuum, regardless of its wavelength or frequency, it travels at the speed of light, c. Because c is constant, the product of λ and f is always the same, so if one gets larger, the other gets smaller. Electromagnetic radiation also, under certain conditions, exhibits a particle-like nature. The particles are called photons, and it is helpful to think of them as energy packets having a welldefined wavelength and frequency. In the early part of this century, Albert Einstein demonstrated that the energy of these photons, E, is directly proportional to their frequency: E = hf where h is a constant called Planck s constant (see Appendix III). The frequency of electromagnetic radiation is inversely proportional to its wavelength, so its energy is, too. Radiation with a long wavelength has less energy than short-wavelength radiation. 7

2 THE SUN-EARTH SYSTEM Absorption and Emission of Electromagnetic Radiation Absorption Suppose that electromagnetic radiation of a given frequency strikes a hydrogen atom and that the frequency is such that the energy of the radiation equals the difference in the energy of the ground and first excited levels of the atom. Then an electron in the ground level may be raised to the first excited level. This process is called absorption. Because the atom has a unique set of energy levels, each will absorb radiation over a particular set of wavelengths. The pattern of wavelengths absorbed is called the absorption spectrum of the atom or molecule. The radiation has vanished (been absorbed), but the total energy of the radiation and the atom energy is conserved. The atom now has more energy than it did. Emission Line Emission Just as a ball kicked up a hill will roll back down to the bottom, the electron very quickly returns to its lowest possible energy level (usually within a hundred-millionth of a second). On the way back to its ground level it must release energy, and it emits the energy as radiation that has the same wavelength as the radiation that first hit the atom. So if the atom is being given energy by some means (such as radiation or collisions with other particles), we can expect to find it emitting electromagnetic radiation at wavelengths governed by the difference in these energy levels. This kind of radiation is called line emission, because when the individual wavelengths are measured with an instrument called a spectrograph, the results show up as lines on a photographic plate. Figure 4. Energy-level diagram for hydrogen. Arrows indicate direction of electron transitions. When the electron moves from a higher to a lower energy level, a photon is emitted; the atom emits energy. When a photon of the right energy strikes the hydrogen atom, the electron moves from a lower to a higher energy level. The atom absorbs energy. Figure 5. Relative amounts of energy emitted by the sun at different wavelengths. Note that most of this energy occurs in the visible region, which extends from about 400 nm to 750 nm. 8

3 THE NATURE OF ELECTROMAGNETIC RADIATION Continuous Emission When the density of atoms in a given area is sufficiently high, the radiation that ultimately leaves the area is smeared into a continuous distribution of wavelengths made up of the many separate wavelengths that the individual atoms emit. This is called continuous emission. The radiation we receive from the Sun is continuous radiation. Figure 5 shows a graph of the relative amount of energy of different wavelengths that the Earth receives from the Sun. Blackbody Radiation The type of continuous radiation the Sun emits is often called blackbody radiation. There are many special features of this type of radiation that allow us to determine various properties of the objects emitting it. One is that the total amount of energy the blackbody emits is determined solely by its temperature. Specifically, the amount of energy that a body emits increases as the fourth power of the temperature. The mathematical expression for this is the Stefan-Boltzmann law: E = σ T 4 where s is a constant (the Stefan-Boltzmann constant; see Appendix III). When the temperature of a blackbody doubles, for example, the amount of energy emitted increases by a factor of two to the fourth power, or 16 (two multiplied by itself four times: 2x2x2x2). A blackbody whose temperature is 4,000 K emits 16 times as much energy as one at 2,000 K. The energy emitted by a blackbody always peaks at some wavelength and decreases toward longer and shorter wavelengths. Figure 5 shows the energy curve for an object at 5,800 K, the approximate temperature of the surface of the Sun. In fact, there is a simple equation, called Wien s displacement law, to determine the temperature of an object by measuring this peak in the energy curve. The equation is: λ max T = x 10 6 where wavelength is in nanometers and temperature is in kelvins. (Note that the constant is very close to 3.0 x 10 6, which is useful for rough calculations.) Wien s law and the Stefan- Boltzmann law are central to understanding the greenhouse effect, discussed in Section III. The Electromagnetic Spectrum The continuous emission spectrum an object radiates is a display of the amount of energy it emits at all wavelengths. The entire electromagnetic spectrum covers an enormous range of wavelengths, divided into regions. Going from the shortest wavelengths to the longest, there are: gamma rays, x-rays, ultraviolet radiation, visible light, infrared radiation, and radio waves. Figure 6 shows the various regions of the spectrum and their approximate wavelength ranges. The visible region occupies only a small portion of the entire spectrum. As Figure 5 shows, the vast majority of our Sun s energy is emitted in the visible, ultraviolet, and infrared ranges. In fact, about 41% of the energy emitted from the Sun lies in the visible bands alone, between 390 nm and 750 nm. Since the surface temperature of the Sun is about 5,800 K, we can calculate from Wien s displacement law that the maximum amount of energy is emitted at about 500 nm, right in the middle of the visible spectrum. About 50% of the energy the Sun emits lies in the infrared and radio regions, above 750 nm, and only about 9% is in the ultraviolet, x-ray, and gamma-ray regions, below 390 nm. It is this electromagnetic radiation, of all wavelengths and frequencies, that determines what effect the Sun s energy has on the Earth and its climate. We have seen that one of the ways electromagnetic radiation interacts with atoms (and molecules) is by being absorbed by them, and that very soon afterward it is emitted again. The energy is taken away but then given back. Does this mean, then, that there is no net 9

4 THE SUN-EARTH SYSTEM effect on the amount of radiation traversing the atmosphere? Indeed, it does not. The radiation being absorbed by an atom is moving in a given direction (for example, from the Sun to the Earth). The radiation that the atom emits may go in any direction with about equal probability. So at the wavelength being absorbed, only an insignificant fraction of the original radiation will continue moving in the original direction, and there will be a net loss of energy in the direction the radiation was originally traveling. Therefore, how much energy, at various wavelengths, is lost from the beam of radiation depends on what atoms and molecules (and how many of them per unit volume) are in its path. So it is the makeup of our atmosphere that determines how much of the Sun s energy gets to the Earth s surface (as well as how much leaves the Earth). Figure 6. The electromagnetic spectrum consists of many regions. Each differs in wavelength, frequency, and energy. 10

5 THE NATURE OF ELECTROMAGNETIC RADIATION THE STEFAN-BOLTZMANN LAW AND THE EARTH S TEMPERATURE Using the Stefan-Boltzmann law, we should be able to determine the approximate average temperature of the Earth, if we assume that the Earth emits the same amount of energy each second that it absorbs from the Sun; that is, that the Earth, on average, is neither heating up nor cooling down. The Stefan-Boltzmann law tells us how much radiant energy per second per unit area an object at a given temperature emits. We know the Sun s temperature, so we can calculate this value for the sun. Multiplying this number by the Sun s surface area gives us the total energy the Sun emits each second. To figure out what fraction of this the Earth receives, imagine, as we did in earlier, a huge sphere with a radius equal to the distance between the Sun and Earth. Imagine a round spot the size of a cross section of Earth pasted on the surface of that sphere. If we divide the cross sectional area of the Earth (the size of the spot) by the surface area of the imaginary sphere, and multiply this fraction by the total energy emitted by the Sun, we have the amount of energy per second the Earth receives from the Sun. Assume the Earth absorbs all of this energy. It must lose the same amount as it gains each second if it is to remain at a constant temperature. We know from the above calculation how much energy the Earth receives and loses. Now we can use the Stefan-Boltzmann law to calculate what temperature the Earth must be to radiate away that amount of energy. It works out at 279 K. To get that number, we simplified some things; we assumed that all the Sun s radiation made it to the Earth s surface and that all the Earth s radiation left unimpeded. The actual average temperature of the Earth is about 288 K. To obtain this number we must take into account the natural greenhouse warming and the fact that about 30% of the Sun s radiation is reflected away and thus does not heat the Earth. These effects will be discussed later. Problems 1. In calculating the temperature of the Earth, we assumed that all of the Sun s energy was absorbed by the Earth and its atmosphere. In fact, only about 70% of this energy is absorbed. The rest is reflected and scattered by the atmosphere and Earth s surface. (This is another way of saying that the albedo of the Earth is about 30%.) What would the Earth s temperature be if its albedo were only 10%? 2. How much solar energy would be collected by a 3-foot by 5-foot solar collector on a clear day if the collector absorbs 95% of this energy, and if 70% of the solar radiation penetrates the atmosphere? 3. What is the energy difference in the two levels of hydrogen that absorb radiation at nm? This line is called the H α line and is one of the most important spectral lines in astrophysics. It is the first line of the Balmer series, and the two energy levels involved are the first and second excited levels. 4. At what wavelength does the maximum radiation occur for an O-type star with a temperature of 30,000 K? This type of star appears blue, since much more radiation is emitted at shorter, blue, than longer, red, wavelengths. 5. How much more energy per second per square meter does the star in Problem 4 emit than the Sun? 6. What is the temperature of an M-type star whose maximum radiation is at 1,000 nm? 11

Take away concepts. What is Energy? Solar Energy. EM Radiation. Properties of waves. Solar Radiation Emission and Absorption

Take away concepts. What is Energy? Solar Energy. EM Radiation. Properties of waves. Solar Radiation Emission and Absorption Take away concepts Solar Radiation Emission and Absorption 1. 2. 3. 4. 5. 6. Conservation of energy. Black body radiation principle Emission wavelength and temperature (Wein s Law). Radiation vs. distance

More information

From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation?

From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation? From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation? From lowest energy to highest energy, which of the following correctly

More information

Solar Energy. Outline. Solar radiation. What is light?-- Electromagnetic Radiation. Light - Electromagnetic wave spectrum. Electromagnetic Radiation

Solar Energy. Outline. Solar radiation. What is light?-- Electromagnetic Radiation. Light - Electromagnetic wave spectrum. Electromagnetic Radiation Outline MAE 493R/593V- Renewable Energy Devices Solar Energy Electromagnetic wave Solar spectrum Solar global radiation Solar thermal energy Solar thermal collectors Solar thermal power plants Photovoltaics

More information

Light as a Wave. The Nature of Light. EM Radiation Spectrum. EM Radiation Spectrum. Electromagnetic Radiation

Light as a Wave. The Nature of Light. EM Radiation Spectrum. EM Radiation Spectrum. Electromagnetic Radiation The Nature of Light Light and other forms of radiation carry information to us from distance astronomical objects Visible light is a subset of a huge spectrum of electromagnetic radiation Maxwell pioneered

More information

Name Date Class ELECTRONS IN ATOMS. Standard Curriculum Core content Extension topics

Name Date Class ELECTRONS IN ATOMS. Standard Curriculum Core content Extension topics 13 ELECTRONS IN ATOMS Conceptual Curriculum Concrete concepts More abstract concepts or math/problem-solving Standard Curriculum Core content Extension topics Honors Curriculum Core honors content Options

More information

5. The Nature of Light. Does Light Travel Infinitely Fast? EMR Travels At Finite Speed. EMR: Electric & Magnetic Waves

5. The Nature of Light. Does Light Travel Infinitely Fast? EMR Travels At Finite Speed. EMR: Electric & Magnetic Waves 5. The Nature of Light Light travels in vacuum at 3.0. 10 8 m/s Light is one form of electromagnetic radiation Continuous radiation: Based on temperature Wien s Law & the Stefan-Boltzmann Law Light has

More information

Radiation Transfer in Environmental Science

Radiation Transfer in Environmental Science Radiation Transfer in Environmental Science with emphasis on aquatic and vegetation canopy media Autumn 2008 Prof. Emmanuel Boss, Dr. Eyal Rotenberg Introduction Radiation in Environmental sciences Most

More information

Principle of Thermal Imaging

Principle of Thermal Imaging Section 8 All materials, which are above 0 degrees Kelvin (-273 degrees C), emit infrared energy. The infrared energy emitted from the measured object is converted into an electrical signal by the imaging

More information

The Earth s Atmosphere

The Earth s Atmosphere THE SUN-EARTH SYSTEM III The Earth s Atmosphere Composition and Distribution of the Atmosphere The composition of the atmosphere and the way its gases interact with electromagnetic radiation determine

More information

Sample Exercise 6.1 Concepts of Wavelength and Frequency

Sample Exercise 6.1 Concepts of Wavelength and Frequency Sample Exercise 6.1 Concepts of Wavelength and Frequency Two electromagnetic waves are represented in the margin. (a) Which wave has the higher frequency? (b) If one wave represents visible light and the

More information

The Sun and Solar Energy

The Sun and Solar Energy I The Sun and Solar Energy One of the most important forces behind global change on Earth is over 90 million miles distant from the planet. The Sun is the ultimate, original source of the energy that drives

More information

TOPIC 5 (cont.) RADIATION LAWS - Part 2

TOPIC 5 (cont.) RADIATION LAWS - Part 2 TOPIC 5 (cont.) RADIATION LAWS - Part 2 Quick review ELECTROMAGNETIC SPECTRUM Our focus in this class is on: UV VIS lr = micrometers (aka microns) = nanometers (also commonly used) Q1. The first thing

More information

Overview. What is EMR? Electromagnetic Radiation (EMR) LA502 Special Studies Remote Sensing

Overview. What is EMR? Electromagnetic Radiation (EMR) LA502 Special Studies Remote Sensing LA502 Special Studies Remote Sensing Electromagnetic Radiation (EMR) Dr. Ragab Khalil Department of Landscape Architecture Faculty of Environmental Design King AbdulAziz University Room 103 Overview What

More information

WAVES AND ELECTROMAGNETIC RADIATION

WAVES AND ELECTROMAGNETIC RADIATION WAVES AND ELECTROMAGNETIC RADIATION All waves are characterized by their wavelength, frequency and speed. Wavelength (lambda, ): the distance between any 2 successive crests or troughs. Frequency (nu,):

More information

Chemistry 2 Chapter 13: Electrons in Atoms Please do not write on the test Use an answer sheet! 1 point/problem 45 points total

Chemistry 2 Chapter 13: Electrons in Atoms Please do not write on the test Use an answer sheet! 1 point/problem 45 points total Chemistry 2 Chapter 13: Electrons in Atoms Please do not write on the test Use an answer sheet! 1 point/problem 45 points total 1. Calculate the energy in joules of a photon of red light that has a frequency

More information

ESCI 107/109 The Atmosphere Lesson 2 Solar and Terrestrial Radiation

ESCI 107/109 The Atmosphere Lesson 2 Solar and Terrestrial Radiation ESCI 107/109 The Atmosphere Lesson 2 Solar and Terrestrial Radiation Reading: Meteorology Today, Chapters 2 and 3 EARTH-SUN GEOMETRY The Earth has an elliptical orbit around the sun The average Earth-Sun

More information

The Electromagnetic Spectrum

The Electromagnetic Spectrum INTRODUCTION The Electromagnetic Spectrum I. What is electromagnetic radiation and the electromagnetic spectrum? What do light, X-rays, heat radiation, microwaves, radio waves, and gamma radiation have

More information

Chapter 2: Solar Radiation and Seasons

Chapter 2: Solar Radiation and Seasons Chapter 2: Solar Radiation and Seasons Spectrum of Radiation Intensity and Peak Wavelength of Radiation Solar (shortwave) Radiation Terrestrial (longwave) Radiations How to Change Air Temperature? Add

More information

Treasure Hunt. Lecture 2 How does Light Interact with the Environment? EMR Principles and Properties. EMR and Remote Sensing

Treasure Hunt. Lecture 2 How does Light Interact with the Environment? EMR Principles and Properties. EMR and Remote Sensing Lecture 2 How does Light Interact with the Environment? Treasure Hunt Find and scan all 11 QR codes Choose one to watch / read in detail Post the key points as a reaction to http://www.scoop.it/t/env202-502-w2

More information

Photons. ConcepTest 27.1. 1) red light 2) yellow light 3) green light 4) blue light 5) all have the same energy. Which has more energy, a photon of:

Photons. ConcepTest 27.1. 1) red light 2) yellow light 3) green light 4) blue light 5) all have the same energy. Which has more energy, a photon of: ConcepTest 27.1 Photons Which has more energy, a photon of: 1) red light 2) yellow light 3) green light 4) blue light 5) all have the same energy 400 nm 500 nm 600 nm 700 nm ConcepTest 27.1 Photons Which

More information

Chapter 18: The Structure of the Atom

Chapter 18: The Structure of the Atom Chapter 18: The Structure of the Atom 1. For most elements, an atom has A. no neutrons in the nucleus. B. more protons than electrons. C. less neutrons than electrons. D. just as many electrons as protons.

More information

Chemistry 102 Summary June 24 th. Properties of Light

Chemistry 102 Summary June 24 th. Properties of Light Chemistry 102 Summary June 24 th Properties of Light - Energy travels through space in the form of electromagnetic radiation (EMR). - Examples of types of EMR: radio waves, x-rays, microwaves, visible

More information

Production of X-rays. Radiation Safety Training for Analytical X-Ray Devices Module 9

Production of X-rays. Radiation Safety Training for Analytical X-Ray Devices Module 9 Module 9 This module presents information on what X-rays are and how they are produced. Introduction Module 9, Page 2 X-rays are a type of electromagnetic radiation. Other types of electromagnetic radiation

More information

PTYS/ASTR 206 Section 2 Spring 2007 Homework #2 (Page 1/5) NAME: KEY

PTYS/ASTR 206 Section 2 Spring 2007 Homework #2 (Page 1/5) NAME: KEY PTYS/ASTR 206 Section 2 Spring 2007 Homework #2 (Page 1/5) NAME: KEY Due Date: start of class 2/6/2007 5 pts extra credit if turned in before 9:00AM (early!) (To get the extra credit, the assignment must

More information

Blackbody radiation derivation of Planck s radiation low

Blackbody radiation derivation of Planck s radiation low Blackbody radiation derivation of Planck s radiation low 1 Classical theories of Lorentz and Debye: Lorentz (oscillator model): Electrons and ions of matter were treated as a simple harmonic oscillators

More information

D.S. Boyd School of Earth Sciences and Geography, Kingston University, U.K.

D.S. Boyd School of Earth Sciences and Geography, Kingston University, U.K. PHYSICAL BASIS OF REMOTE SENSING D.S. Boyd School of Earth Sciences and Geography, Kingston University, U.K. Keywords: Remote sensing, electromagnetic radiation, wavelengths, target, atmosphere, sensor,

More information

The Phenomenon of Photoelectric Emission:

The Phenomenon of Photoelectric Emission: The Photoelectric Effect. The Wave particle duality of light Light, like any other E.M.R (electromagnetic radiation) has got a dual nature. That is there are experiments that prove that it is made up of

More information

After a wave passes through a medium, how does the position of that medium compare to its original position?

After a wave passes through a medium, how does the position of that medium compare to its original position? Light Waves Test Question Bank Standard/Advanced Name: Question 1 (1 point) The electromagnetic waves with the highest frequencies are called A. radio waves. B. gamma rays. C. X-rays. D. visible light.

More information

Atomic Structure Ron Robertson

Atomic Structure Ron Robertson Atomic Structure Ron Robertson r2 n:\files\courses\1110-20\2010 possible slides for web\atomicstructuretrans.doc I. What is Light? Debate in 1600's: Since waves or particles can transfer energy, what is

More information

Astronomy 110 Homework #04 Assigned: 02/06/2007 Due: 02/13/2007. Name:

Astronomy 110 Homework #04 Assigned: 02/06/2007 Due: 02/13/2007. Name: Astronomy 110 Homework #04 Assigned: 02/06/2007 Due: 02/13/2007 Name: Directions: Listed below are twenty (20) multiple-choice questions based on the material covered by the lectures this past week. Choose

More information

Objectives 404 CHAPTER 9 RADIATION

Objectives 404 CHAPTER 9 RADIATION Objectives Explain the difference between isotopes of the same element. Describe the force that holds nucleons together. Explain the relationship between mass and energy according to Einstein s theory

More information

Energy. Mechanical Energy

Energy. Mechanical Energy Principles of Imaging Science I (RAD119) Electromagnetic Radiation Energy Definition of energy Ability to do work Physicist s definition of work Work = force x distance Force acting upon object over distance

More information

Teaching Time: One-to-two 50-minute periods

Teaching Time: One-to-two 50-minute periods Lesson Summary Students create a planet using a computer game and change features of the planet to increase or decrease the planet s temperature. Students will explore some of the same principles scientists

More information

Electromagnetic Radiation (EMR) and Remote Sensing

Electromagnetic Radiation (EMR) and Remote Sensing Electromagnetic Radiation (EMR) and Remote Sensing 1 Atmosphere Anything missing in between? Electromagnetic Radiation (EMR) is radiated by atomic particles at the source (the Sun), propagates through

More information

Use the following image to answer the next question. 1. Which of the following rows identifies the electrical charge on A and B shown above?

Use the following image to answer the next question. 1. Which of the following rows identifies the electrical charge on A and B shown above? Old Science 30 Physics Practice Test A on Fields and EMR Test Solutions on the Portal Site Use the following image to answer the next question 1. Which of the following rows identifies the electrical charge

More information

Blackbody radiation. Main Laws. Brightness temperature. 1. Concepts of a blackbody and thermodynamical equilibrium.

Blackbody radiation. Main Laws. Brightness temperature. 1. Concepts of a blackbody and thermodynamical equilibrium. Lecture 4 lackbody radiation. Main Laws. rightness temperature. Objectives: 1. Concepts of a blackbody, thermodynamical equilibrium, and local thermodynamical equilibrium.. Main laws: lackbody emission:

More information

MAKING SENSE OF ENERGY Electromagnetic Waves

MAKING SENSE OF ENERGY Electromagnetic Waves Adapted from State of Delaware TOE Unit MAKING SENSE OF ENERGY Electromagnetic Waves GOALS: In this Part of the unit you will Learn about electromagnetic waves, how they are grouped, and how each group

More information

a) species of plants that require a relatively cool, moist environment tend to grow on poleward-facing slopes.

a) species of plants that require a relatively cool, moist environment tend to grow on poleward-facing slopes. J.D. McAlpine ATMS 611 HMWK #8 a) species of plants that require a relatively cool, moist environment tend to grow on poleward-facing slopes. These sides of the slopes will tend to have less average solar

More information

1. At which temperature would a source radiate the least amount of electromagnetic energy? 1) 273 K 3) 32 K 2) 212 K 4) 5 K

1. At which temperature would a source radiate the least amount of electromagnetic energy? 1) 273 K 3) 32 K 2) 212 K 4) 5 K 1. At which temperature would a source radiate the least amount of electromagnetic energy? 1) 273 K 3) 32 K 2) 212 K 4) 5 K 2. How does the amount of heat energy reflected by a smooth, dark-colored concrete

More information

Wave Function, ψ. Chapter 28 Atomic Physics. The Heisenberg Uncertainty Principle. Line Spectrum

Wave Function, ψ. Chapter 28 Atomic Physics. The Heisenberg Uncertainty Principle. Line Spectrum Wave Function, ψ Chapter 28 Atomic Physics The Hydrogen Atom The Bohr Model Electron Waves in the Atom The value of Ψ 2 for a particular object at a certain place and time is proportional to the probability

More information

Structure and Properties of Atoms

Structure and Properties of Atoms PS-2.1 Compare the subatomic particles (protons, neutrons, electrons) of an atom with regard to mass, location, and charge, and explain how these particles affect the properties of an atom (including identity,

More information

PHOTOELECTRIC EFFECT AND DUAL NATURE OF MATTER AND RADIATIONS

PHOTOELECTRIC EFFECT AND DUAL NATURE OF MATTER AND RADIATIONS PHOTOELECTRIC EFFECT AND DUAL NATURE OF MATTER AND RADIATIONS 1. Photons 2. Photoelectric Effect 3. Experimental Set-up to study Photoelectric Effect 4. Effect of Intensity, Frequency, Potential on P.E.

More information

The Three Heat Transfer Modes in Reflow Soldering

The Three Heat Transfer Modes in Reflow Soldering Section 5: Reflow Oven Heat Transfer The Three Heat Transfer Modes in Reflow Soldering There are three different heating modes involved with most SMT reflow processes: conduction, convection, and infrared

More information

Rate Equations and Detailed Balance

Rate Equations and Detailed Balance Rate Equations and Detailed Balance Initial question: Last time we mentioned astrophysical masers. Why can they exist spontaneously? Could there be astrophysical lasers, i.e., ones that emit in the optical?

More information

Solar Flux and Flux Density. Lecture 3: Global Energy Cycle. Solar Energy Incident On the Earth. Solar Flux Density Reaching Earth

Solar Flux and Flux Density. Lecture 3: Global Energy Cycle. Solar Energy Incident On the Earth. Solar Flux Density Reaching Earth Lecture 3: Global Energy Cycle Solar Flux and Flux Density Planetary energy balance Greenhouse Effect Vertical energy balance Latitudinal energy balance Seasonal and diurnal cycles Solar Luminosity (L)

More information

Atomic Structure: Chapter Problems

Atomic Structure: Chapter Problems Atomic Structure: Chapter Problems Bohr Model Class Work 1. Describe the nuclear model of the atom. 2. Explain the problems with the nuclear model of the atom. 3. According to Niels Bohr, what does n stand

More information

STAAR Science Tutorial 30 TEK 8.8C: Electromagnetic Waves

STAAR Science Tutorial 30 TEK 8.8C: Electromagnetic Waves Name: Teacher: Pd. Date: STAAR Science Tutorial 30 TEK 8.8C: Electromagnetic Waves TEK 8.8C: Explore how different wavelengths of the electromagnetic spectrum such as light and radio waves are used to

More information

ATOMIC SPECTRA. Apparatus: Optical spectrometer, spectral tubes, power supply, incandescent lamp, bottles of dyed water, elevating jack or block.

ATOMIC SPECTRA. Apparatus: Optical spectrometer, spectral tubes, power supply, incandescent lamp, bottles of dyed water, elevating jack or block. 1 ATOMIC SPECTRA Objective: To measure the wavelengths of visible light emitted by atomic hydrogen and verify the measured wavelengths against those predicted by quantum theory. To identify an unknown

More information

Homework #4 Solutions ASTR100: Introduction to Astronomy Fall 2009: Dr. Stacy McGaugh

Homework #4 Solutions ASTR100: Introduction to Astronomy Fall 2009: Dr. Stacy McGaugh Homework #4 Solutions ASTR100: Introduction to Astronomy Fall 2009: Dr. Stacy McGaugh Chapter 5: #50 Hotter Sun: Suppose the surface temperature of the Sun were about 12,000K, rather than 6000K. a. How

More information

Review 1. Multiple Choice Identify the choice that best completes the statement or answers the question.

Review 1. Multiple Choice Identify the choice that best completes the statement or answers the question. Review 1 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. When hydrogen nuclei fuse into helium nuclei a. the nuclei die. c. particles collide. b. energy

More information

Engineering Mini Holiday Lights

Engineering Mini Holiday Lights 1 Engineering Mini Holiday Lights Jeffrey La Favre The small light bulbs we are using for our activities were cut from strings of mini holiday lights. The strings contained 100 light bulbs arranged in

More information

Energy Pathways in Earth s Atmosphere

Energy Pathways in Earth s Atmosphere BRSP - 10 Page 1 Solar radiation reaching Earth s atmosphere includes a wide spectrum of wavelengths. In addition to visible light there is radiation of higher energy and shorter wavelength called ultraviolet

More information

AZ State Standards. Concept 3: Conservation of Energy and Increase in Disorder Understand ways that energy is conserved, stored, and transferred.

AZ State Standards. Concept 3: Conservation of Energy and Increase in Disorder Understand ways that energy is conserved, stored, and transferred. Forms of Energy AZ State Standards Concept 3: Conservation of Energy and Increase in Disorder Understand ways that energy is conserved, stored, and transferred. PO 1. Describe the following ways in which

More information

Austin Peay State University Department of Chemistry Chem 1111. The Use of the Spectrophotometer and Beer's Law

Austin Peay State University Department of Chemistry Chem 1111. The Use of the Spectrophotometer and Beer's Law Purpose To become familiar with using a spectrophotometer and gain an understanding of Beer s law and it s relationship to solution concentration. Introduction Scientists use many methods to determine

More information

Blackbody Radiation References INTRODUCTION

Blackbody Radiation References INTRODUCTION Blackbody Radiation References 1) R.A. Serway, R.J. Beichner: Physics for Scientists and Engineers with Modern Physics, 5 th Edition, Vol. 2, Ch.40, Saunders College Publishing (A Division of Harcourt

More information

ATM S 111, Global Warming: Understanding the Forecast

ATM S 111, Global Warming: Understanding the Forecast ATM S 111, Global Warming: Understanding the Forecast DARGAN M. W. FRIERSON DEPARTMENT OF ATMOSPHERIC SCIENCES DAY 1: OCTOBER 1, 2015 Outline How exactly the Sun heats the Earth How strong? Important concept

More information

Basics of Nuclear Physics and Fission

Basics of Nuclear Physics and Fission Basics of Nuclear Physics and Fission A basic background in nuclear physics for those who want to start at the beginning. Some of the terms used in this factsheet can be found in IEER s on-line glossary.

More information

Infrared Spectroscopy: Theory

Infrared Spectroscopy: Theory u Chapter 15 Infrared Spectroscopy: Theory An important tool of the organic chemist is Infrared Spectroscopy, or IR. IR spectra are acquired on a special instrument, called an IR spectrometer. IR is used

More information

Practice final for Basic Physics spring 2005 answers on the last page Name: Date:

Practice final for Basic Physics spring 2005 answers on the last page Name: Date: Practice final for Basic Physics spring 2005 answers on the last page Name: Date: 1. A 12 ohm resistor and a 24 ohm resistor are connected in series in a circuit with a 6.0 volt battery. Assuming negligible

More information

Level 3 Achievement Scale

Level 3 Achievement Scale Unit 1: Atoms Level 3 Achievement Scale Can state the key results of the experiments associated with Dalton, Rutherford, Thomson, Chadwick, and Bohr and what this lead each to conclude. Can explain that

More information

MASS DEFECT AND BINDING ENERGY

MASS DEFECT AND BINDING ENERGY MASS DEFECT AND BINDING ENERGY The separate laws of Conservation of Mass and Conservation of Energy are not applied strictly on the nuclear level. It is possible to convert between mass and energy. Instead

More information

CHAPTER 2 Energy and Earth

CHAPTER 2 Energy and Earth CHAPTER 2 Energy and Earth This chapter is concerned with the nature of energy and how it interacts with Earth. At this stage we are looking at energy in an abstract form though relate it to how it affect

More information

ILLUSTRATIVE EXAMPLE: Given: A = 3 and B = 4 if we now want the value of C=? C = 3 + 4 = 9 + 16 = 25 or 2

ILLUSTRATIVE EXAMPLE: Given: A = 3 and B = 4 if we now want the value of C=? C = 3 + 4 = 9 + 16 = 25 or 2 Forensic Spectral Anaylysis: Warm up! The study of triangles has been done since ancient times. Many of the early discoveries about triangles are still used today. We will only be concerned with the "right

More information

Electromagnetic Radiation Energy that comes to us from the sun is transported in the form of waves known as electromagnetic energy.

Electromagnetic Radiation Energy that comes to us from the sun is transported in the form of waves known as electromagnetic energy. Electromagnetic Radiation Energy that comes to us from the sun is transported in the form of waves known as electromagnetic energy. This combines electricity and magnetism such that setting up an electric

More information

8.1 Radio Emission from Solar System objects

8.1 Radio Emission from Solar System objects 8.1 Radio Emission from Solar System objects 8.1.1 Moon and Terrestrial planets At visible wavelengths all the emission seen from these objects is due to light reflected from the sun. However at radio

More information

Light. What is light?

Light. What is light? Light What is light? 1. How does light behave? 2. What produces light? 3. What type of light is emitted? 4. What information do you get from that light? Methods in Astronomy Photometry Measure total amount

More information

CHEM 1411 Chapter 5 Homework Answers

CHEM 1411 Chapter 5 Homework Answers 1 CHEM 1411 Chapter 5 Homework Answers 1. Which statement regarding the gold foil experiment is false? (a) It was performed by Rutherford and his research group early in the 20 th century. (b) Most of

More information

The photoionization detector (PID) utilizes ultraviolet

The photoionization detector (PID) utilizes ultraviolet Chapter 6 Photoionization Detectors The photoionization detector (PID) utilizes ultraviolet light to ionize gas molecules, and is commonly employed in the detection of volatile organic compounds (VOCs).

More information

Photosynthesis and Light in the Ocean Adapted from The Fluid Earth / Living Ocean Heather Spalding, UH GK-12 program

Photosynthesis and Light in the Ocean Adapted from The Fluid Earth / Living Ocean Heather Spalding, UH GK-12 program Photosynthesis and Light in the Ocean Adapted from The Fluid Earth / Living Ocean Heather Spalding, UH GK-12 program Algae, like your Halimeda, and plants live in very different environments, but they

More information

Physics 1010: The Physics of Everyday Life. TODAY Black Body Radiation, Greenhouse Effect

Physics 1010: The Physics of Everyday Life. TODAY Black Body Radiation, Greenhouse Effect Physics 1010: The Physics of Everyday Life TODAY Black Body Radiation, Greenhouse Effect 1 Admin Stuff Exams are at back of room, alphabetically in four piles. Please collect AFTER class Grades posted

More information

TIME OF COMPLETION NAME SOLUTION DEPARTMENT OF NATURAL SCIENCES. PHYS 3650, Exam 2 Section 1 Version 1 October 31, 2005 Total Weight: 100 points

TIME OF COMPLETION NAME SOLUTION DEPARTMENT OF NATURAL SCIENCES. PHYS 3650, Exam 2 Section 1 Version 1 October 31, 2005 Total Weight: 100 points TIME OF COMPLETION NAME SOLUTION DEPARTMENT OF NATURAL SCIENCES PHYS 3650, Exam 2 Section 1 Version 1 October 31, 2005 Total Weight: 100 points 1. Check your examination for completeness prior to starting.

More information

Chapter 7. Electron Structure of the Atom. Chapter 7 Topics

Chapter 7. Electron Structure of the Atom. Chapter 7 Topics Chapter 7 Electron Structure of the Atom Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Chapter 7 Topics 1. Electromagnetic radiation 2. The Bohr model of

More information

Waves Sound and Light

Waves Sound and Light Waves Sound and Light r2 c:\files\courses\1710\spr12\wavetrans.doc Ron Robertson The Nature of Waves Waves are a type of energy transmission that results from a periodic disturbance (vibration). They are

More information

THERMAL RADIATION (THERM)

THERMAL RADIATION (THERM) UNIVERSITY OF SURREY DEPARTMENT OF PHYSICS Level 2 Classical Laboratory Experiment THERMAL RADIATION (THERM) Objectives In this experiment you will explore the basic characteristics of thermal radiation,

More information

18.2 Comparing Atoms. Atomic number. Chapter 18

18.2 Comparing Atoms. Atomic number. Chapter 18 As you know, some substances are made up of only one kind of atom and these substances are called elements. You already know something about a number of elements you ve heard of hydrogen, helium, silver,

More information

Main properties of atoms and nucleus

Main properties of atoms and nucleus Main properties of atoms and nucleus. Atom Structure.... Structure of Nuclei... 3. Definition of Isotopes... 4. Energy Characteristics of Nuclei... 5. Laws of Radioactive Nuclei Transformation... 3. Atom

More information

Electron Orbits. Binding Energy. centrifugal force: electrostatic force: stability criterion: kinetic energy of the electron on its orbit:

Electron Orbits. Binding Energy. centrifugal force: electrostatic force: stability criterion: kinetic energy of the electron on its orbit: Electron Orbits In an atom model in which negatively charged electrons move around a small positively charged nucleus stable orbits are possible. Consider the simple example of an atom with a nucleus of

More information

A n = 2 to n = 1. B n = 3 to n = 1. C n = 4 to n = 2. D n = 5 to n = 2

A n = 2 to n = 1. B n = 3 to n = 1. C n = 4 to n = 2. D n = 5 to n = 2 North arolina Testing Program EO hemistry Sample Items Goal 4 1. onsider the spectrum for the hydrogen atom. In which situation will light be produced? 3. Which color of light would a hydrogen atom emit

More information

Atomic Calculations. 2.1 Composition of the Atom. number of protons + number of neutrons = mass number

Atomic Calculations. 2.1 Composition of the Atom. number of protons + number of neutrons = mass number 2.1 Composition of the Atom Atomic Calculations number of protons + number of neutrons = mass number number of neutrons = mass number - number of protons number of protons = number of electrons IF positive

More information

Arrangement of Electrons in Atoms

Arrangement of Electrons in Atoms CHAPTER 4 PRE-TEST Arrangement of Electrons in Atoms In the space provided, write the letter of the term that best completes each sentence or best answers each question. 1. Which of the following orbital

More information

Using the Spectrophotometer

Using the Spectrophotometer Using the Spectrophotometer Introduction In this exercise, you will learn the basic principals of spectrophotometry and and serial dilution and their practical application. You will need these skills to

More information

AP Physics B Ch. 23 and Ch. 24 Geometric Optics and Wave Nature of Light

AP Physics B Ch. 23 and Ch. 24 Geometric Optics and Wave Nature of Light AP Physics B Ch. 23 and Ch. 24 Geometric Optics and Wave Nature of Light Name: Period: Date: MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Reflection,

More information

13- What is the maximum number of electrons that can occupy the subshell 3d? a) 1 b) 3 c) 5 d) 2

13- What is the maximum number of electrons that can occupy the subshell 3d? a) 1 b) 3 c) 5 d) 2 Assignment 06 A 1- What is the energy in joules of an electron undergoing a transition from n = 3 to n = 5 in a Bohr hydrogen atom? a) -3.48 x 10-17 J b) 2.18 x 10-19 J c) 1.55 x 10-19 J d) -2.56 x 10-19

More information

Name Class Date. spectrum. White is not a color, but is a combination of all colors. Black is not a color; it is the absence of all light.

Name Class Date. spectrum. White is not a color, but is a combination of all colors. Black is not a color; it is the absence of all light. Exercises 28.1 The Spectrum (pages 555 556) 1. Isaac Newton was the first person to do a systematic study of color. 2. Circle the letter of each statement that is true about Newton s study of color. a.

More information

Preview of Period 3: Electromagnetic Waves Radiant Energy II

Preview of Period 3: Electromagnetic Waves Radiant Energy II Preview of Period 3: Electromagnetic Waves Radiant Energy II 3.1 Radiant Energy from the Sun How is light reflected and transmitted? What is polarized light? 3.2 Energy Transfer with Radiant Energy How

More information

Objectives. PAM1014 Introduction to Radiation Physics. Constituents of Atoms. Atoms. Atoms. Atoms. Basic Atomic Theory

Objectives. PAM1014 Introduction to Radiation Physics. Constituents of Atoms. Atoms. Atoms. Atoms. Basic Atomic Theory PAM1014 Introduction to Radiation Physics Basic Atomic Theory Objectives Introduce and Molecules The periodic Table Electronic Energy Levels Atomic excitation & de-excitation Ionisation Molecules Constituents

More information

Physical Science Study Guide Unit 7 Wave properties and behaviors, electromagnetic spectrum, Doppler Effect

Physical Science Study Guide Unit 7 Wave properties and behaviors, electromagnetic spectrum, Doppler Effect Objectives: PS-7.1 Physical Science Study Guide Unit 7 Wave properties and behaviors, electromagnetic spectrum, Doppler Effect Illustrate ways that the energy of waves is transferred by interaction with

More information

8.2 Cells and Energy. What is photosynthesis? Photosynthesis takes place in the chloroplasts. CHAPTER 8. Solar cells and chloroplasts

8.2 Cells and Energy. What is photosynthesis? Photosynthesis takes place in the chloroplasts. CHAPTER 8. Solar cells and chloroplasts CHAPTER 8 CELL PROCESSES 8.2 Cells and Energy To stay alive, you need a constant supply of energy. You need energy to move, think, grow, and even sleep. Where does that energy come from? It all starts

More information

Using Photometric Data to Derive an HR Diagram for a Star Cluster

Using Photometric Data to Derive an HR Diagram for a Star Cluster Using Photometric Data to Derive an HR Diagram for a Star Cluster In In this Activity, we will investigate: 1. How to use photometric data for an open cluster to derive an H-R Diagram for the stars and

More information

Atoms Absorb & Emit Light

Atoms Absorb & Emit Light Atoms Absorb & Emit Light Spectra The wavelength of the light that an element emits or absorbs is its fingerprint. Atoms emit and absorb light First Test is Thurs, Feb 1 st About 30 multiple choice questions

More information

MCQ - ENERGY and CLIMATE

MCQ - ENERGY and CLIMATE 1 MCQ - ENERGY and CLIMATE 1. The volume of a given mass of water at a temperature of T 1 is V 1. The volume increases to V 2 at temperature T 2. The coefficient of volume expansion of water may be calculated

More information

British Physics Olympiad

British Physics Olympiad 1 British Physics Olympiad Paper 3. 2005 Monday 28 February 2005. Time allowed 3hrs plus 15 minutes reading time. All questions should be attempted. Question 1 carries 40 marks, the other questions 20

More information

2 Absorbing Solar Energy

2 Absorbing Solar Energy 2 Absorbing Solar Energy 2.1 Air Mass and the Solar Spectrum Now that we have introduced the solar cell, it is time to introduce the source of the energy the sun. The sun has many properties that could

More information

Current Staff Course Unit/ Length. Basic Outline/ Structure. Unit Objectives/ Big Ideas. Properties of Waves A simple wave has a PH: Sound and Light

Current Staff Course Unit/ Length. Basic Outline/ Structure. Unit Objectives/ Big Ideas. Properties of Waves A simple wave has a PH: Sound and Light Current Staff Course Unit/ Length August August September September October Unit Objectives/ Big Ideas Basic Outline/ Structure PS4- Types of Waves Because light can travel through space, it cannot be

More information

Review Vocabulary spectrum: a range of values or properties

Review Vocabulary spectrum: a range of values or properties Standards 7.3.19: Explain that human eyes respond to a narrow range of wavelengths of the electromagnetic spectrum. 7.3.20: Describe that something can be seen when light waves emitted or reflected by

More information

PRACTICE EXAM IV P202 SPRING 2004

PRACTICE EXAM IV P202 SPRING 2004 PRACTICE EXAM IV P202 SPRING 2004 1. In two separate double slit experiments, an interference pattern is observed on a screen. In the first experiment, violet light (λ = 754 nm) is used and a second-order

More information

Spectrophotometry and the Beer-Lambert Law: An Important Analytical Technique in Chemistry

Spectrophotometry and the Beer-Lambert Law: An Important Analytical Technique in Chemistry Spectrophotometry and the Beer-Lambert Law: An Important Analytical Technique in Chemistry Jon H. Hardesty, PhD and Bassam Attili, PhD Collin College Department of Chemistry Introduction: In the last lab

More information

The Earth's Atmosphere. Layers of the Earth's Atmosphere

The Earth's Atmosphere. Layers of the Earth's Atmosphere The Earth's Atmosphere The atmosphere surrounds Earth and protects us by blocking out dangerous rays from the sun. The atmosphere is a mixture of gases that becomes thinner until it gradually reaches space.

More information

Chapter NP-5. Nuclear Physics. Nuclear Reactions TABLE OF CONTENTS INTRODUCTION OBJECTIVES 1.0 NUCLEAR REACTIONS 2.0 NEUTRON INTERACTIONS

Chapter NP-5. Nuclear Physics. Nuclear Reactions TABLE OF CONTENTS INTRODUCTION OBJECTIVES 1.0 NUCLEAR REACTIONS 2.0 NEUTRON INTERACTIONS Chapter NP-5 Nuclear Physics Nuclear Reactions TABLE OF CONTENTS INTRODUCTION OBJECTIVES 1.0 2.0 NEUTRON INTERACTIONS 2.1 ELASTIC SCATTERING 2.2 INELASTIC SCATTERING 2.3 RADIATIVE CAPTURE 2.4 PARTICLE

More information

9/13/2013. However, Dalton thought that an atom was just a tiny sphere with no internal parts. This is sometimes referred to as the cannonball model.

9/13/2013. However, Dalton thought that an atom was just a tiny sphere with no internal parts. This is sometimes referred to as the cannonball model. John Dalton was an English scientist who lived in the early 1800s. Dalton s atomic theory served as a model for how matter worked. The principles of Dalton s atomic theory are: 1. Elements are made of

More information