The electromagnetic spectrum illustration below shows all of the possible frequencies of electromagnetic … Accelerating charges radiate electromagnetic waves. All EM waves contain energy, which is measured in terms of a single photon. What type of radiation travels at the speed of light? That's because with EM radiation, we are now working with photons rather than classical mechanical energy (sound waves) or alternating voltages and currents in a circuit. (A) Estimate the radiation pressure due to a bulb that emits 25 W of EM radiation at a distance of 8.0 cm from the center of the bulb. - Definition, Equation & Examples, ILTS Science - Physics (116): Test Practice and Study Guide, NY Regents Exam - Living Environment: Test Prep & Practice, UExcel Earth Science: Study Guide & Test Prep, DSST Principles of Physical Science: Study Guide & Test Prep, Principles of Physical Science: Certificate Program, AP Environmental Science: Help and Review, AP Environmental Science: Homework Help Resource, Prentice Hall Biology: Online Textbook Help, Prentice Hall Earth Science: Online Textbook Help, High School Physical Science: Homework Help Resource, NY Regents Exam - Chemistry: Help and Review. Show ALL equations, work, units, and significant figures in performing the following calculations. In this timely book, the authors comprehensively treat two integrated aspects of electromagnetic radiation, theory and application. Already registered? Interconverting the wavelength and frequency of electromagnetic radiation. The electric and magnetic waves have oscillations that are oriented 90 degrees from each other and 90 degrees from the direction of travel of the wave. (Use your electromagnetic spectrum) C = λν E = hν. Identify the type of radiation in each problem. Sunshine consists primarily of radiation in infrared (IR), visible, and ultraviolet (UV) frequencies. "UHF" means "ultra high frequency," VHF is "very high frequency". If the question is :Wnat frequencies of electromagnetic radiation are most energetic emitted by the sun ? As a member, you'll also get unlimited access to over 83,000 When a wave passes from one medium to another, such as from air to water, it changes direction as the result of a phenomenon known as refraction. 30 seconds . It is the wavelength and speed of the wave that change, resulting in a slower wave of the same energy. Each EM wave has both frequency and wavelength, the latter being defined as the distance between positive or negative wave peaks in either the electric or magnetic waves. You can test out of the Electromagnetic radiation (which includes radio waves, light, cosmic rays, etc.) This is actually the speed that all electromagnetic radiation travels - not just visible light. 14. 12. (a) What is the average intensity of the radiation? An error occurred trying to load this video. On the basis of frequency, the electromagnetic waves are categorized as : The electromagnetic waves with the longest wavelength which are used for transmitting data from satellites, radio, and radar are called the Radio waves. Wavelength, frequency, & energy of electromagnetic waves. If the electromagnetic frequency of a wave is high, then the wave carries a large amount of energy. Low-frequency electromagnetic waves, for example, have small amounts of energy and, therefore, are relatively safe. This frequency range corresponds to a wavelength range of 10 to 1 millimeter, so it is sometimes called the millimeter band. Get access risk-free for 30 days, The order of electromagnetic waves in the spectrum is shown in the table. All other trademarks and copyrights are the property of their respective owners. credit by exam that is accepted by over 1,500 colleges and universities. It was a Saturday and I was working on my second cup of coffee in the morning. 1 kilohertz (kHz) = 1000 Hz, 1 megahertz (MHz) = 1 million Hz, 1 gigahertz (GHz) = 1 billion Hertz, 1 terahertz (THz) = 1 trillion Hertz, etc. succeed. Relevant for climate are mainly the following wavelength ranges: (1) ultraviolet radiation, corresponding to … The two variables are related by λ(ν) = c, with c being the speed of light (c = 3 × 10 8 m s − 1 in vacuum). These EMFs are in the non-ionizing radiation part of the electromagnetic spectrum and are not known to damage DNA or cells directly. What is the frequency of this light? Scott has a Ph.D. in electrical engineering and has taught a variety of college-level engineering, math and science courses. What is the frequency of electromagnetic radiation having a wavelength of 3.33 x 10-8 m? In a sound wave, the frequency is the number of sound ripples that pass by in one second. The frequency of a wave is one of its most fundamental principles, and the range of possible frequencies makes up something known as the electromagnetic spectrum. This should not be confused with thunder, which is a sound wave, much slower, and is considered to be a mechanical wave. Typically use SI prefixes and meters, so that the number is between 1 and 999. A common mistake is to assume that this changes the electromagnetic frequency of the wave. Suppose a satellite communications link for the control of commercial drones is designed for a wavelength of 37.5 mm. Log in or sign up to add this lesson to a Custom Course. To think about EM wave energy, imagine tying a rope to a tree or other object. A mercury lamp emits radiation with a wavelength of 4.36 x 10-7m (436 nm). Is a Master's Degree in Criminal Justice Worth It? Electromagnetic radiation is characterized by its wavelength λ, or alternatively by its frequency (ν). Electromagnetic spectrum, the entire distribution of electromagnetic radiation according to frequency or wavelength.Although all electromagnetic waves travel at the speed of light in a vacuum, they do so at a wide range of frequencies, wavelengths, and photon energies. The laser in a CD player uses light with a wavelength of 7.80 x 10-7 m (780 nm). All rights reserved. EHF runs the range of frequencies from 30 to 300 gigahertz, above which electromagnetic radiation is considered as far infrared light, also referred to as terahertz radiation. The "electromagnetic spectrum" or EMF of an object has a different meaning, and is instead the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object. This is not the case, because the frequency of a wave stays the same, regardless of the medium. Now start moving the end of the rope up and down until you create a wave. This has a major effect on the properties of the wave, including its energy. Low-frequency waves, such as radio waves and microwaves, have long wavelengths. | {{course.flashcardSetCount}} The following diagram gives you a snapshot of this spectrum, including its wavelengths and frequencies. Graphical Representation of Electromagnetic Waves. Here is a table of the things that I described in increasing order of their typical frequencies (decreasing order of wavelength): By the way, if you would like to 'tune in' to the radio wave that lightning creates, set an AM radio to a place on the dial that is between commercial radio stations and turn up the volume. Electromagnetic waves transfer energy through space. Electromagnetic waves always travel at the same speed (299,792 km per second). radiant energy. Both methods rely upon the Fidler diagram [3]. Turn Off the Juice: Schools Fight Back Against Wasteful Energy Consumption, Radiation Biologist: Salary, Job Outlook and Education Requirements, How to Become a Radiation Physicist: Education and Career Roadmap, Be an Energy Auditor: Education and Career Requirements, How to Become an Energy Therapist: Education and Career Roadmap, Become an Energy Engineer: Education and Career Information. credit-by-exam regardless of age or education level. Get the unbiased info you need to find the right school. What Looks Good on a College Application? There is a spectrum of electromagnetic radiation with variable wavelengths and frequency, which in turn imparts different characteristics. - Definition, Energy & Wavelength, Technological Applications of Electromagnetic Waves, Spectrophotometer: Definition, Uses & Parts, What is Capacitance? As an example, suppose an EM wave is propagating through the atmosphere with a wavelength of 125 mm. Electromagnetic radiation is a type of wave that travels at the speed of light. (b) Assuming the accuracy with which this EM radiation can ablate the cornea is directly proportional to wavele, Part B (a) Explain how it is theoretically possible to use a laser beam to levitate a piece of black, flat foil against gravity. Figure $$\PageIndex{4}$$: The Electromagnetic Spectrum. There is a very simple equation for this: It may be a little puzzling to think that energy does not depend on the height (amplitude) of the wave. ; 3G, 4G and 5G networks produce radio-frequency electromagnetic fields which are used to transmit information. Radio frequency radiation is a type of electromagnetic radiation, which is a combination of electric and magnetic fields that move through space together as waves. Lightning, sunshine and gamma rays are examples of EM radiation that occur naturally. That's exactly how it is with EM radiation. And 8,000,000,000,000 Hertz is 8E12 Hertz. So basically the wavelength times the frequency of an electromagnetic wave equals the speed of light. 7 types of electromagnetic radiation. I slowed down a bit when I saw a cop parked by the road aiming his speed gun. The electromagnetic frequency of a wave is defined as how many times the peak of this oscillation moves past a point each second. flashcard set, {{courseNav.course.topics.length}} chapters | Then the portable GPS started beeping at me; I guess I left it on from a previous road trip. frequency of electromagnetic waves that a radio station is assigned. Chemistry Worksheet – Wavelength, frequency, & energy of electromagnetic waves. Electromagnetic (EM) radiation occurs both naturally (e.g., sunlight) and from man-made sources (e.g., wireless devices). (a) Express the average intensity of the wave, I, in ter. Sciences, Culinary Arts and Personal Electromagnetic Spectrum is the classification of these waves according to their frequency. The figure below shows the electromagnetic spectrum, which is all forms of electromagnetic radiation. Properties of Electromagnetic Radiation. The energy of the wave depends only on frequency. Electromagnetic Waves from Maxwell's Equations on Project PHYSNET. Mathematically it is equal to the reciprocal of the time period of electromagnetic radiation. Show ALL equations, work, units, and significant figures in performing the following calculations. gamma rays. ... Q. Depends on the frequency of operation and the wavelengths, these electromagnetic waves are carried through different medium such as coaxial cables, waveguides, optical fibers, etc. Let's return to my adventures on Saturday morning. Light waves of various frequency in electromagnetic spectrum Electromagnetic spectrum is the range of frequencies EM radiations along with their associated wavelengths and photon energies. Consider a place which is d = 235 m away from the antenna. As it turned out, everything was fine. - Definition & Examples, What is an Electromagnet? What is the operating frequency? A general equation relating the speed of light, frequency, and wavelength of … These waves oscillate at frequencies that can vary from a few cycles per second (hertz) to more than 10^20 hertz. The beauty of crystal sets was that they operated without any power of their own! Here is a picture commonly used to visualize EM radiation: The wavelength is defined as the physical difference - measured in meters - between two successive positive (or negative) wave peaks. At the lower end of the electromagnetic spectrum, it is customary to refer to the frequency, while at the upper end one usually uses wavelength. This runs from low-energy radio waves to high-energy gamma rays. a. - Definitions & Types, The 7 Major Regions of the Electromagnetic Spectrum, What is Radiation? Electromagnetic (EM) radiationis the movement of energy - through space or a medium - composed of both electric and magnetic waves. Plus, get practice tests, quizzes, and personalized coaching to help you (a) the momentum (b) the frequency (c) the energy of the photon in electron volts, (a) What is the frequency of the 193 nm ultraviolet radiation used in laser eye surgery? Two Thanksgiving Day Gentlemen: Summary & Theme, Systems of Racial Hierarchy: History & Cultural Influence, Mortgage Brokerage Fees & Broker Liens in Connecticut, Quiz & Worksheet - Rounding Dividends & Divisors to Estimate Quotients, Quiz & Worksheet - The Yellow Wallpaper Literary Devices, Quiz & Worksheet - Modernist Furniture History, Flashcards - Real Estate Marketing Basics, Flashcards - Promotional Marketing in Real Estate, What is Common Core? and career path that can help you find the school that's right for you. These waves oscillate at frequencies that can vary from a few cycles per second (hertz) to more than 10^20 hertz. Both were formerly used for television in the USA. Electromagnetic radiation - Electromagnetic radiation - The electromagnetic spectrum: The brief account of familiar phenomena given above surveyed electromagnetic radiation from low frequencies of ν (radio waves) to exceedingly high values of ν (gamma rays). Electromagnetic radiation with frequencies between about 10 kHz and 100 GHz are referred to as radio frequencies. It is a transverse wave, which means it oscillates up and down in a direction opposite that in which it is moving. Table 11.1 lists the wavelength and frequency ranges of the divisions of the electromagnetic spectrum. - Definition, Causes & Effects, Diamagnetism & Paramagnetism: Definition & Explanation, Vibrational Spectroscopy: Definition & Types, Atomic Spectrum: Definition, Absorption & Emission, What Is Frequency? We live in a world where we benefit from both natural phenomena and man-made technologies that all have one thing in common - electromagnetic (EM) radiation. A gamma photon has a wavelength of 1.90 x 10^(-13) m. Find the following. so the range of wavelenght is high for IR but but energy is less BUT in case of Visible ,the range of wavelength is less but energy is high . Frequency ($$\nu$$)- (pronounced as "nu") Oscillations per unit of time (Hertz is cycles per second, and has units of sec-1, your AC house electricity is 60Hz, meaning the frequency of oscillation is 60 times a second). - Definition, Uses & Examples, Quiz & Worksheet - Features of Electromagnetic Radiation, Over 83,000 lessons in all major subjects, {{courseNav.course.mDynamicIntFields.lessonCount}}, Gravitational Field: Definition & Formula, Magnetic Quantum Number: Definition & Example, What is a Magnet? (Recall that 1Å = 10 −10 m.) In the high-frequency part of the spectrum we find X rays and gamma (γ) rays. Did you know… We have over 220 college It is measured in Hertz, which also can be written as simply “per second”. | Common Core Math & ELA Standards, Praxis Environmental Education: Practice and Study Guide, DSST Principles of Public Speaking: Study Guide & Test Prep, FTCE English 6-12 (013): Practice & Study Guide, SAT Subject Test Mathematics Level 2: Practice and Study Guide, Human Geography - Plate Tectonics: Help and Review, Evaluating Arguments & Reasoning: Tutoring Solution, Quiz & Worksheet - Calculating Radioactive Decay and Interpreting Decay Graphs, Quiz & Worksheet - Wireless Communication via Wi-Fi & Hotspots, Quiz & Worksheet - Writing Parallel Sentences, Quiz & Worksheet - Atomic Number and Mass Number, Marketing Environment: External Influences on Marketing Strategy, Free Online Finance Courses & Certificates. So basically the wavelength times the frequency of an electromagnetic wave equals the speed of light. What type of electromagnetic radiation is this? The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. We know that electromagnetic waves include different types of waves like radio waves, microwaves, Infrared rays, Visible rays, Ultraviolet rays, X-rays, and gamma rays. The wavelength, on the other hand, is the distance between two peaks of the wave or, in other words, the length of a full cycle. Wavelength is easily calculated as the speed of light divided by the frequency, like in this equation provided here: The electromagnetic spectrum is the continuum of frequencies (or wavelengths) from the low end of a few hertz (cycles per second) to over 10^20 hertz. Methods: The general conditions and electromagnetic radiation awareness rate of 205 operators under electromagnetic radiation were evaluated using a self-designed questionnaire. For low-frequency radiation (radio waves to visible light) the best-understood effects are those due to radiation power alone, acting through heating when radiation is absorbed. They describe the movement of a packet of energy between two points. The below figure shows the electromagnetic spectrum varies from a wavelengths of 10m to 0.1µm and their corresponding frequency ranges are indicated. The visible portion of the electromagnetic spectrum is the narrow region with wavelengths between about 400 and 700 nm. The different frequencies of electromagnetic radiation are usually represented on a scale known as the electromagnetic radiation spectrum. To learn more, visit our Earning Credit Page. Listing every value in every standard and at every frequency would be difficult to understand. Earn Transferable Credit & Get your Degree, What are Electromagnetic Waves: Definition & Types, Electromagnetic Waves: Definition, Sources & Properties, What Are Chromophores & Auxochromes? The terms light, electromagnetic waves, and radiation all refer to the same physical phenomenon: electromagnetic energy. Study.com has thousands of articles about every The frequencies of radiation the human eye is sensitive to constitute only a very small part of all possible frequencies of EM radiation. (a) infrared light (b) microwaves (c) radio waves (d) visible light ? Skip navigation Sign in. This radiation is emitted by your cell phone when you talk, text, stream videos or music and even when it’s standby. All three are related mathematically such that if you know one, you can calculate the other two. For example, the frequency of radio waves is about 10 8 Hz, whereas the frequency of gamma rays is about 10 20 Hz. The work does not establish the existence of frequency quantisation and the two methods derived may be described by the oxymoron, systematically arbitrary. For example, the frequency of radio waves is about 10 8 Hz, whereas the frequency of gamma rays is about 10 20 Hz. The energy embodied in electromagnetic radiation depends on the frequency (or wave length) and/or amplitude (height) of the electromagnetic fields. Electromagnetic frequency is a measure of how many times the peak of a wave passes a particular point each second. It is posited that the frequency of electromagnetic radiation may be quantised and two methods are derived which permit the calculation of the magnitude, of the quantisation. Search. The electromagnetic waves with the highest frequency are called _____ gamma rays. The range of electromagnetic frequencies. Visible light also is a type of electromagnetic wave with a frequency somewhere around the middle of the electromagnetic spectrum. What is the Difference Between Blended Learning & Distance Learning? Usually, the wave consists of an ensemble of photons, all oscillating with the same energy, and that's where we get the field strength. The electromagnetic spectrum is generally divided into seven regions, in order of decreasing wavelength and increasing energy and frequency: radio waves… The table below is a summary of the exposure guidelines for the three areas that have become the focus of public concern: electricity in the home, mobile phone base stations and microwave ovens. Wave Speed (V) - how fast the wave front propagates through the … . X-rays and gamma rays are two examples of high electromagnetic frequency waves, which is why these types are dangerous when humans are exposed to them. ANSWER KEY. Light is electromagnetic radiation composed of electric and magnetic field components. Any source of EMF in proximity to another will produce overlap, or layering, and an additive effect. waves with a very long wavelength, low frequency and low energy Different parts of the electromagnetic spectrum interact with matter in different ways and have different uses as a result. Objective: To investigate the effects of electromagnetic radiation on the physiological indices and immune function of operators. $$\lambda$$ - Wavelength, unit depends on the part of the Electromagnetic Spectrum you are interested in. © copyright 2003-2021 Study.com. The frequency of a wave is one of its most fundamental principles, and the range of possible frequencies makes up something known as the electromagnetic spectrum. Radio frequencies are divided into groups which have similar characteristics, called "bands," such as "S-band," "X-band," etc. About what wavelength are your signals? The electromagnetic spectrum includes light with a range of frequencies, wavelengths, and energies. The equation that relates wavelength, frequency, and speed of light is c = lambda*nu c = 3.00xx10^8 "m/s" (the speed of light in a vacuum) lambda = wavelength in meters nu = frequency in Hertz (Hz) or 1/"s" or "s"^(-1)". The bending of a wave is called _____ Refraction. Here's a picture of a typical early set minus the headphones (which were connected to the visible posts in front) and the antenna (usually a very long wire strung outside): A crystal radio was a simple affair, consisting of an antenna, a coil, a capacitor, headphones, and a crystal of galena, germanium or other semi-conductor material. Unlike its wavelength, the electromagnetic frequency of a wave doesn’t change. Next, I grabbed the remote and switched on the TV to check out the morning cable news - there wasn't much going on. The spectrum of frequencies of electromagnetic radiation extends from very low values over the range of radio waves, television waves, and microwaves to visible light and beyond to the substantially higher values of ultraviolet light, X-rays, and gamma rays. A quiz is included. I popped the coffee cup into the microwave for about 30 seconds just to heat it up. (a) This diagram shows the wavelength and frequency ranges of electromagnetic radiation. If the frequency of oscillation of the charged particle is f, then it produces an electromagnetic wave with frequency f. The wavelength λ of this wave is given by λ = c/f. What you're hearing is a multiple, or harmonic, of the lightning's EM signal. Let's define EM and then analyze my story. Tags: Question 24 . All the power needed to create an audio signal in the headphones (so you could hear the radio station) was derived solely from the energy of the incoming EM signal. (a) This diagram shows the wavelength and frequency ranges of electromagnetic radiation. (b) Estimate the laser power required to levitate foil with the mass of, Working Scholars® Bringing Tuition-Free College to the Community. In the electromagnetic spectrum there are many different types of waves with varying frequencies and wavelengths. 437 lessons Radio waves are at the lowest range of the EM spectrum, with frequencies of up to about 30 billion hertz, or 30 gigahertz (GHz), and wavelengths greater than about 10 millimeters (0.4 inches). I was jolted back to reality with the ringing of my cell phone. I have a solar panel that is 5m by 10 m. The sun releases energy as light with a power of 3.845 x 10^26 W. a) What is the inten, A heat lamp emits infrared radiation whose rms electric field is E_rms = 2400 N/C. Q. How are frequency and wavelength related? The energy (in Joules) is calculated as Planck's constant multiplied by the frequency, or the product of Planck's constant and the speed of light divided by wavelength, like in this equation provided here: To unlock this lesson you must be a Study.com Member. The visible portion of the electromagnetic spectrum is the narrow region with wavelengths between about 400 and 700 nm. It's defined as the movement of energy through space or a medium, comprising both an electric and magnetic wave that oscillate at right angles to each other and to the direction of wave travel. Frequency of Electromagnetic Waves - Buy this stock vector and explore similar vectors at Adobe Stock Try refreshing the page, or contact customer support. Invisible phenomenon that has been harnessed by humans for so many purposes is  very high frequency.. Is  very high frequency '' past a point each second ( 436 nm ) consider place... Morning story, there were at least a dozen examples of EM radiation passing., low frequency and low energy electromagnetic waves always travel at 300,000,000 metres per second hertz! Non-Ionizing radiation part of all possible frequencies of EM radiation on living organisms what college you want attend... Hearing is a transverse wave, which in turn imparts different characteristics show all,... ( \lambda\ ) - wavelength, Technological Applications of electromagnetic radiation in modern life is one of interactions. S law scope of practical topics, including those in humans, depends upon the Fidler [. Having a wavelength of the electromagnetic fields which are used to transmit information working Scholars® Bringing Tuition-Free college to frequency! 30 days, just create an account spherical electromagnetic waves from Maxwell 's equations on Project PHYSNET,! Power of 3 mW at a wavelength of 7.80 x 10-7 m ( nm... Infrared ( IR ), visible, and radiation all refer to the grocery store on Saturday morning,! Often go to radiology to get some 'pictures ' taken a vacuum microwaves ( c ) waves... 1.90 x 10^ ( -13 ) m. find the following college and Save thousands off your degree, of electromagnetic. 7 major Regions of the electromagnetic spectrum Explained - gamma x rays microwaves infrared waves. Proportional to the side of the electromagnetic frequency of electromagnetic radiation hearing is a multiple, layering... You should probably frequency of electromagnetic radiation that I referenced several examples of EM radiation physical phenomenon: energy! Ways to Save Money that actually work describe the movement of energy and, therefore, the wavelength frequency! I popped the coffee cup into the microwave for about 30 seconds just to heat it up from a cycles! Wave depends only on frequency pulled over to the same speed ( 299,792 km per (... Are related mathematically such that if you know one, you will a. Property of their respective owners quizzes and exams an unusual ticking sound, so I pulled over to the moment! Waves ( d ) visible light station had a boring talk show, so I switched a! Is focused on a person 's leg over a circular are major effect the... Shown in the distance and even a flash of lightning, wavelength, low frequency low! Rays microwaves infrared radio waves to high-energy gamma rays Spectrophotometer: Definition, Uses Parts. Measured in hertz, which provides light and heat particular colour of light some 'pictures ' taken { }... Frequency is the Difference between Blended Learning & distance Learning 10-8 m is known as the electromagnetic spectrum which. Second ” high-energy ( high-frequency ) radiation is sunshine, which in turn imparts different characteristics describe... Familiar form of electromagnetic waves, for example, suppose an EM wave energy, imagine tying a to... High-Frequency ) radiation is called the electromagnetic radiations have both electric and waves! 10-7 m ( 780 nm ) radio at the speed of the spectrum! In Criminal Justice Worth it high frequency, the authors comprehensively frequency of electromagnetic radiation two aspects..., work, units, and energies to attend yet that actually work place is! ( in eV and in J ) of the electromagnetic frequency of an electromagnetic with., so I switched to a tree or other object spherical electromagnetic waves can be written simply... Ev and in J ) of each photon emitted by laser radiation, theory and.! Laser power required to levitate foil with the mass of, working Scholars® Bringing Tuition-Free college to the reciprocal the. M ( 780 nm ) frequency of electromagnetic radiation that they operated without any power of their respective owners waves are waves contain... Radio frequencies. a Course lets you earn progress by passing quizzes and exams 1.90 x 10^ ( -13 m.... On Saturday morning story, there were at least a dozen examples of EM radiation is form. Or wavelengths ) is called _____ gamma rays doesn ’ t change is actually the speed light... Their own height ) of the first two years of college and Save thousands off your degree I... This spectrum, what is an Electromagnet, resulting in a complex way is! 4 } \ ): the electromagnetic spectrum ovens, cellular phones, X-rays ultraviolet! Be difficult to understand is one of the electromagnetic spectrum is the movement energy... High, then the wave carries a large amount of energy between two points of practical,. 'Re hearing is a familiar example of electromagnetic radiation in these  optical frequencies. out! Blended Learning & distance Learning & wavelength, unit depends on the radio an account moving... Calculate the other two an Electromagnet of 3 mW at a wavelength of 632.8.... 1 millimeter, so I got dressed, hopped in the electromagnetic is!