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112 Cards in this Set
- Front
- Back
What does greater warmth entale? |
greater molecular motion, attributed to the energy of light. |
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What is radiative energy? |
The energy that carries light |
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What are teh three forms of energy |
radiative energy |
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What is a joules, what is power? what is a watt? |
a joules is a unit to measure energy. power is the rate of energy flow, and we measure power in units called wats. 1 watt is equal to one joules |
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Define spectrum |
the basic colors in a rainbow like spectrum are red, orange, yellow, green, blue and violet, we see white when these colors are mixed in roughly equal proportions. white light contains all the colors of teh rainbow. |
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what is black? |
it is what we see when there is no light and hense no color. |
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What are the primary colors of vision? |
red, green and blue. they are the colors directly detected by cells in your eyes. |
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what is cmyk? |
the artistpalat. cyan, magenta, yellow and black mixed to create a great variety of colors. |
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In which ways can you produce a spectrum of color? |
a prism or a diffraction grating. |
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what is a diffraction grating. |
a piece of plastic or glass etched with many closely spaced lines. |
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How do light and matter interact? 4 |
emission absorption transmission and reflection/scattering |
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what is emission? |
the energy of the light comes from electrical potential energy supplied to the bulb. |
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What is absorption? |
when you place your hand near an incandescent light bulb your hand absorbs some of the light. |
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Transmission |
some forms of matter such as glass or air transmit light, which means allowing light to pass through |
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what is reflection/scattering? |
light can bounce off matter, leading to what we call reflection. scattering is when the bouncing is more random. |
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what are the differences between transparent and opaque? |
transparent is see through opaque is not. these options are variable. |
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What is vision? |
your brain interpreting the light. |
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Who provided the first insights into the nature of light? |
Isaac Newton in 1660's. He did an experiment with two prisms, the first seperated the light, the second put it back together. |
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What are the differences between particles and waves? |
individual atoms and molecules are particles. they can sit still or can move. |
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what are the three basic properties of waves? |
wavelength, frequency and speed. |
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what is wavelength? |
the distance from one peak to the next, or between troughs. |
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What is Frequency? |
the number of peaks passing by any point each second. |
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What are cycles per second? |
often called herts, units of frequency. |
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What is speed? |
tells us how fast the peaks travel across the pond. because a wave carries energy the speed essentially tells us how fast hte energy travels. |
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How do soundwaves travel? |
through the air causing air molecules to vibrate back and force. the vibrations of matter allow the waves to transmit energy from one place to another. |
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What is waving when a light passes by? what is electric and magnetic fields? |
A feild discribes the strength of a force that a particle would experience at any given point in space. |
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what is a gravitational field? |
describes teh strength of gravity at any distance from earth |
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Why is light an electromagnetic wave? |
vibrations of the electric field in an electromagnetic wave cause any charged partacle to bob up and down. |
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How do you tell the frequency and wavelength between electronmagnetic waves? |
the distence between peaks tells us the wavelength while the number of times each electron bobs tells us the frequency. |
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What is the speed of light? |
300,000 kilometers per second |
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How do wavelengths and frequencys interact? |
because all light travels the same speed and that speed is the wavelength times the frequency, the important relationship between the two is that the longer the wavelength the lower the frequency and vice versa. |
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What are photons? |
particles of light. Light behaves as both a wave and a particle. light comes in individual pieces called photons that have properties of both particle and waves. each photon is caracterized by a wavelength and a frequency. each photon caries a specific amunt of radiative energy. |
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what is the relationship between radiation and photons? |
the shorter the wavelength of the light or, the higher the frequency, the higher the energy(radiation) of the photons. |
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What is an electromagnetic spectrum? |
the complete spectrum of light, including that which we cannot see. |
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what is electromagnetic radiation? |
light. |
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How is the electromagnetic spectrum divided? |
gregions, according to wavelength, frequency, or energy. Everything in the spectrum represents a form of light and therefore consists of photons that travel through space at the speed of light. |
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Explain visable light |
light that is found near the middle of the spectrum that our eyes can see. this liht ranges from about 400 nanometers at the red end |
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what is a nanometer |
a nanometer is a billionth of a meter |
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what is infared |
wevelengths somewhat longer than red light that lies beyond the red end of teh rainbow. molecules moving around in a warm object emit infared light. |
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what are radio waves |
the longest wavelength light. carry so little energy that they have no noticeable effect on our bodies. can make electrons move up and down in an antenna. |
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Microwave |
where wavelengths range from micrometers to centimeters. |
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What are the shorter wavelengths? |
ultraviolet, somewhat shorter than blue light. because it lies beyond the blue end of teh rainbow. ultraviolet wavelengths carry enough energy to harm cells in our skin causing sunburn or cancer. |
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what are xrays? |
light that is even shorter in wavelength than ultraviolet. have enough energy to penetrate through skin and muscle but can be blocked by bones or teeth. |
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what are gamma rays? |
the shortest wavelength. |
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How do light and matter interact? |
Light carries information about matter. |
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Who is Democritus? |
greek philosopher who wondered what would happen if we break a peice of matter , i.e. rock. he claimed that the rock would eventually break into particles so small that nothing smaller could be possible. he called these particles atoms, meaning invisible. |
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How did democritus view the formation of the world? |
he imagined the atoms came together to suggest the universe began as a chaotic mix that lowly clumped together. |
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What are elements |
different types of atoms. |
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Atomic structure. what particles are atoms made up of? |
protons, neutrons and electrons. |
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what is the nucleus? |
center of the atom. protons and neutrons are found inside of it. |
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How are the properties of an atom determined? |
the electricle charge. electricle charge describes how strongly an object will interact with electromagnetic fields. |
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what is an electrical charge? |
a proton is the pasic unit of a positive charge and an electron is preicisely the opposite. neutrons have no charge. oppositely charged particles attract and similiarily charged particles repel. The attraction between positive and negative is what holds an atom together. |
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how do the electrons surround the neucleus? |
they give the atom a smeared out cloud that surrounds the nucleus and gives it an apprarent size. give the atom a size far larger than that of its nucleus even though they represent only a tiny portion of the atoms mass. |
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What is atomic number? what is atomic mass number? |
atomic number is the number of protons in its nucleus. the combined amount of protons and nutrons is the atomic mass. every atom of an element has the exact same number of protons but neutrons may vary. |
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What are isotopes? |
versions of an element that have different numbers of neutrons. |
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What are molecules? |
atoms combined. some molecules consist of two or more atoms of the same element. |
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What are phases of matter? |
solid, liquid, gas |
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what is a chemical bond? |
the name we give to the interactions between electrons that hold the atoms in a molecule together. |
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what are phase changes? |
phases of change when one type of bond is broken and replaced by another. these include ptressure, temperature, both. involves the kinetic energy of its particles. as this energy encreses the particles are able to break the bonds holding them. |
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What are phase changes in water? |
water can be solid, liquid, or gas. low cinetic energy allows them to be tightly bound as a solid ice. always vibrating, the vibrating increases causing melting to turn ice to water. the molecules still have a bond until the energy increases and then they become a gass at 100 degrees celcius. |
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how can the atmosphere have both water and gas phase? |
tempeture is a measure of teh average kinetic energy of particles in a substence. individual particles may have substantially lower or higher energyies than the average. these molecules may have enough energy to break free of their neighbors and enter the gas phase. |
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sublimation and evaporation |
sublimation is the process by which molecules escape from a solid, evaporation is the process in which molecules escape from a liquid. higher tempetures lead to higher instances of these. |
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what is molecular dissociation |
when molecules split into peaices. at higher tempetures the molecules are more violently moving and colisions become so violent that htey can break the chemical bonds. |
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what is ionization? |
at higher tempetures than dissociation collisions can break the bonds holding electrons around the nuclei of individual atoms. this leads to charged atoms called ions. the process of stripping electrons from atoms is called ionization
the degreeof ionization depends on its temperature and composition. hydrogen has only one electron so can only be ionized once. the remaining hydrogen, h+ becomes a proton, is neutral. |
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What is plasma? |
a hot gas which seperates h2o into hydrogen and oxygen, where the atoms have broken apart, loosing their charge and become ionized. |
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how are interactions between light and plasma different from a gas consisting of neutral atoms? |
sometimes referred to the fourth phase of mater. ligitimate to refer to it as a gas. |
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Phases and preasure-- what is pressure? |
the force per unite area pushing on an objects surface. force is also known as weight. |
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how can preasure affect phases? |
inner metal core of earth remains solid even though the temperature is high enough that the metal would melt into liquid under less extreme pressure conditions. ex 2. the greater rate of water vapor molecules in our atmosphere the higher rate at which the molecules return to the ocean. helps stabalize water levels. |
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how is energy stored in atoms? how is light produced? |
to produce light objects must somehow transform energy contained in matter into the vibrations of electric and megnetic fields that we call light. |
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How is light produced? |
must focus on the charged particles within atom, particularily electrons. Only charged particles can interact with light. |
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in what three ways do atoms contain energy? |
virtue of their mass, weight. potential energy depends on the arrangement of teir electrons around their nuclei. |
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What is the property of energy stored by electrons in atoms? |
have only particular amounts of energy, and not other energies in between. like possible hights on a ladder, non adjustable. |
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energy levels? |
possible energies of an atom |
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how can an electron rise from low energy to a higher one or fall back to a lower energy level? |
these are called energy level transitions. and occur only when an electron gains or loses the specific amount of energy seperating the two levels. (ladder analogy). Energy seperating levels gets smaller at higher levels. takes more energy to move between level one and two then level two and three. |
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What happens when an electron gains enough energy to reach ionization leve? |
it escapes the atom completly, thereby ionizing the atom. any excess energy beyond the amoung needed for ionization becomes kenetic energy of the free moving electron. |
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explain quantnized |
the stabilization and restriction of electron levels to certain levels without the freedom to move between. the study of these level is quantum physics. |
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Define spectroscopy |
obtaining a spectrum and reading the information it contains |
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intensity |
amount of energy at each wavelength |
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Continuous spetrum |
one of the three basic types of spectra- a rainbow of color. spans a broad range of wavelengths without interruption.
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Emission line spectrum |
a thin or low density cloud of gas that emits light only at specific wavelengths. consists of bright emission lines against a black background. |
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absorption line spectrum |
if the light of specific wavelenghts is absorbed the spectrum shows dark absorption lines. |
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Emission lne spectra-- how? |
Sometiems collisions transfer the right abount of energy to bump an electron from low to high energy level. this cannot be maintainted. when the electron looses this energy it often goes into emitting a photon of light. must have the same amount of energy that the electron looses which means that it always has a specific wavelength and frequency. the bright emmissions correspond to doward transitions of electrons. the rest of the spectrum is dark. |
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absorption line spectra. |
energy transitions in uppward motion, opposite of emission. |
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What are chemical fingerprints |
hydrogen emits and absorbs light at specific wavelengths so that we can detect its presence in distant objects. spectrums can show fingerprints left by specific atoms. every atom has its own spectral fingerprint. |
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how are chemical fingerprints useful? |
they can allow us to measure the tempetures of far off stars. |
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how do molecules produce spectral fingerprints? |
because hey are made of mor atoms bound together mmolecules can vibrate and rotate. energy changes are usually smaller than those in atoms and produce lower energy photons. |
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what are molecular bands? |
tightly bunched lines within the spectra of molecular light. usually found in the infared portion of the electromagnetic spectrum. |
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What do looking at spectrums of distant objects tell us? |
the spectrums of different molecules and atoms will tell us what the object is made out of. more detailed analysis can even tell us the relative porportions of the elements. this is how we have learned the chemical composition of objects thought the universe. |
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What does the reflected light spectra tell us? |
the mark reflected light leaves on the spectra tells us information about the object. which ever colors are being absorbed represent the colors of what the light is bouncing off of. reflected light gives us the color while absorbed light helps to determine its tempeture. |
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How does light tell us the tmpetures of planets and stars? |
using the continuous spectra. |
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What are attributes of large or dense objects with light and energy? |
tend to absorb light across a broad range of wavelengths. light cannot eeasily pass through and light emmitted within cannot easily escape. |
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What does the spectrum of a dense object depend on? |
tempeture. tempeture represents average kenetic energy. the bouncing molecules and atoms end up with energies that match with the energies of teh objects atoms. photon energies depend only on the tempeture of the object. |
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Thermal radiation |
aka blackbody rdation when the kenetic energies of photons inside an object match the energies of the atoms and molecules within an object. called a thermal radiation spectrum. no real object emits a perfect thermal radiation spectrum. most objects release light that approximates thermal radiation. |
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What are the two laws of thermal radiation? |
A) Each square metre of a hotter objects surface emits more light at all wavelengths than that of a cooler objects surface.
B) Hotter objects emit photons with a higher average energy, this means a shorter average wavelength. |
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What is the Doppler effect? |
causes changes in a spectra of distant objects. determines the sound of waves based on the distance between your self and the object emitting the sound. |
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what are wavelengths and frequencys coherts in the doppler effect? |
frequency is pitch and wavelegth is... |
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How does the doppler effect cause shifts in light? |
if the object move towards us the light bunches up and so the spectrum is shifted to shorter waveleghts. shorter wavelegths are bluer so an object coming twards us is called a blueshift. longer wavelengths are called redshifts. |
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rest wavelengths |
wavelengths at stationary clouds or distances. |
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how can you determine speed by using the doppler effect? |
the shorter the shift of wavelengths becomes, the faster the object is moving towards you. the longer they become, the further away the object is moving from you. |
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how can the doppler effect give us information about motion within an object? |
rotation will make an object appear wider. parts moving away will be redshift, towards blueshift. the faster the rotation the broader the shift in wavelenghts. |
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1) Watt is a What? Oops, sorry… I meant to ask “What is a Watt?”. |
a unit of power |
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2) What property of light determines its “color”? |
The wavelength of a photon determines what color you see. Since the wavelength and |
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3) A camera flash appears to be bright white in color. What does this tell you about |
Objects that look black reflect very little visible light, so what we call black is actually |
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4) A particle of light (a photon) hits an electron. All of the photon’s energy is turned |
In absorption events, the photon is completely swallowed up by matter. It can be |
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5) Which of the following is false? |
Your ear does not detect radio waves. Radio waves are electromagnetic waves with a |
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6) Which of the following phases of a material is the hottest? |
If kept at the same pressure, a solid material will normally melt into a liquid, then boil |
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7) A transparent material |
A transparent material like glass allows most photons of visible light through without |
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8) Why is grass green? |
If a) were true, and grass emitted its own light, it would glow even if there was no |
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9) An atom is missing an electron in one of its electron energy levels, and another |
If the electron drops in energy, that energy has to go somewhere. You can’t create or |
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10) You are looking at a tungsten lamp, which emits a very smooth, continuous |
The light emitted by the tungsten will be absorbed by the hydrogen (if it is at a |
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11) Which effect makes emission lines from far away galaxies look redder than they |
Most galaxies are rapidly receding from us. Because of this, the light that they emit |
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12) You find an ion of a rare isotope of the (hitherto undetected) element |
The atomic number is simply the number of protons (here, 215), and the atomic weight |