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_______________physics 1. Matter is a____________________ 2. Light is a _________________. This is "everyday" physics that deals with objects that are relatively 1. _____________ bigger than _____________ 2. _____________ v << _____ _______________ modified classical physics so that it would give more accurate results when speeds _______________________________ and for________________. His theories are called the ________________ and ________________ Theories of _________________________ . _______________ physics modified physics to deal with _________________________ on the scale of ___________ . According to this theory: 1. Matter can act like a___________________________. 2. Light can act like a___________________________. Ex: Light in the classical view acts like a ___________ whose _________________ determines its energy: _______________ more____________ Ex: The ___________________ effect showed that light can act like a ______________________ . color of light brightness of light how many electrons were ejected from the zinc and with what KE red dim no e- red bright no e- violet dim a few e- with lots of KE violet bright lots of e- with lots of KE Einstein _____________________________ for a paper that explained the photoelectric effect by assuming light acted like ______________. The higher its _______________ the greater the energy of the light particle. Bright light consists of ___________ particles. _______________ light: ________________light: ________________light: ________________light: 1_______ energy particle cannot eject an enone of these many _______ energy particles could eject an e 1_______ energy particle can eject 1 eeach of these many ________ energy particles could eject an e- The ______________ (basic unit) of electromagnetic energy (light) is called a _______________ . It has no mass, but carries ______________ and ________________ . Its energy is given by: Eph = where h= = Ex: What is the relationship between Eph and f? Eph f What quantity does the slope of the line? Ex: What is the relationship between Eph and l? Start with the equation: Substitute c in for v: Solve for f: Substitute in the equation for Ex: What does the graph of Eph vs. l look like? Eph l The greater the wavelength, the ___________ the energy. Ex: Find the energy of a blue light photon in joules. Convert the answer to electronvolts (eV). See page 1 of ESRT: 1 eV = ________________ J _____________ theory - ____________________ energy is emitted from and absorbed by _______________ in _____________ amounts or ________________ . ( ______________ means "separate, individual pieces.") Ex: _______________ of a photon before: atom Ex: _____________ of a photon before: atom after: atom has ______ energy after: atom has _______ energy Ex The ____________Effect: X-rays scatter off electrons. e- at rest KE =____ before collision: after collision: _______ photon e- ____________ The scattered photon now has _______ energy. So its f is _______ and its l is ______________ Both _________________and ______________ are conserved. In sum, light can act like a __________________ or like a ____________ . Which one it acts like depends on the situation. When light interacts with.. … __________ , it acts … ___________ , it acts like a _________________ like a __________________ Examples: Examples: 1/ __________________ 1/ __________________ 2/ __________________ 2/ __________________ 3/ __________________ Even when it is described as a photon, we still use __________ properties such as _______________ and _________________ to describe it. Electron charge: In 1909, Millikan sprayed drops of ________ into an _______________ field E. Fe =___ oil drop Fg =_____ By suspending the oil drop then letting it fall, he was able to discover that the oil drops always carried an ___________________________ of the fundamental charge = ______________________ (the ______________ of charge). which is the charge on 1 _____________ or _____________ . Charge is __________________ . Models of the atom: I. _____________________: In 1897, discovered e-’s were ________ mass and ____________________ charged. Since he also knew that atoms as a whole were ______________, he developed the ______________________________ model: One _________ : negative eare the ____________ positive charge is ________________ distributed in a___________________ _____________________ : In 1909, he fired ___________ particles (positively charged ____________ nuclei) at thin gold foil: only 1 in 8000 were scattered ____________ ________ were not scattered or were scattered through _____________ angles His conclusion: The ___________________________ mass is concentrated in _________________________ at the atom's _____________ . He called this the ________________ of the atom. II. As a result of Rutherford's experiment, the ___________________ model was developed: One atom: ______________charge concentrated in the _____________ The e-'s ___________ the nucleus similar to how ________________ orbit __________________ . size of nucleus ~ ___________________ of ` the diameter of atom _____________________with the solar system model: 1. Circular orbital motion q _________________ 2. Accelerating q ______________emitted from atom 3. Energy radiated orbits will _____________________ 4. All atoms should ___________________in a short time 5. As they collapse, the e- should______________________ and the atom should _____________________emit a higher and higher ______________________ of light 6. This should produce a ____________________spectrum. but _______________ spectra were observed. III. The Bohr model for ___________________: 1. The 1 e- in H____________________ or __________ ____________the nucleus. It __________ in a ___________. 2. The e- can only be found at ______________ (certain specially allowed) distances, which are unfortunately still called __________________ . Each orbital has a _____________ number,____ . a/ The orbital _____________to the nucleus is called the ____________________and has n = ____. It has the ______________ energy = ______________. b/ The orbital furthest from the nucleus has the ______________energy and has n =_____. The energy of that orbital = ____. In that case, the e- is said to be _______________ , which means it is ________________ from the atom completely. ----- = _____________ A. Bohr model of H atom: _________ state of electron proton n= 2 to ∞ are called ____________ states The ______ ecan be found at ______ level etc… e- is___________ B. Photon _________________ : If an e- moves from to a ___________ energy orbital to a __________one, a photon of light is ___________ (given off). photon _________ The ____________ of the emitted photon: Eph = Reference Tables: page 3, top left. Ei = Ef = Eph = Ei – Ef Eph = Eph = = = Easy way: IGNORE NEG. SIGNS AND JUST SUBTRACT!!! C. Photon _________________ : If an e- moves from to a ___________ energy orbital to a __________one, a photon of light is ___________ (taken in). photon _________ The __________ of the absorbed photon: Eph = Ef = Eph = Ei – Ef Eph = Eph = (ignore neg. signs) = Ei = D. Energy ____________________: Emission (the ____________of light): Atom __________ energy as e- moves __________ photon ___________ ___________ atom Absorption (the ____________ of light): photon __________ __________ Atom _________energy atom as e- moves_________ In both cases: _________________ = ___________________ E. NOTES: 1. The technical term for “jumps” is____________________. 2. No _______________________ jumps are allowed!!! Only jumps from one ______________energy level or orbit to another ____________ energy level are allowed. 3. That is why _______________________ energy photons can be emitted or absorbed by atoms.. 4. Since Eph = hf, only certain __________________(colors) are produced. 5. That is why photon energies are ___________________(only certain values are allowed). Eph = Ei – Ef = hf ΔE = amount of e-____________ Bigger e- jumps (transitions) more _________ more _________ _____________ frequency photons in ___________________ and beyond Little e- jumps (transitions) less _________ less _________ _____________ frequency photons in ____________________ and lower This is true for _______________ and _______________ . _______ transitions _______ transitions involve involve _______ energy light _______ energy light Which transitions involve visible light? F. ________________ : Jumps from any level to n = ___ will ___________the e- from the atom. Ionization _________________: The _____________required to ___________an e- from an atom. What is the ionization potential for a H atom that has an electron in the ground state? What is the ionization potential for a H atom that has an electron in the n=3 state? G. So where do _________________ (bright line) and _____________________spectra come from? Unless the source is a low-density gas, interactions with other atoms blur the lines into a _________________ spectrum. The heated gas emits absorbs, then emits only those photons from _____________ energy transitions. The missing colors are the __________ ones that were_____________ by the gas. V. Bohr’s model could NOT explain why e- could only have ______________orbitals and energies. This was later explained by_________________________: The e- acts like a __________ and __________________ interferes with ___________ as it wraps itself around the ________________: orbits This can only occur at certain ______________ distances from the nucleus. VI. The ___________Model: 1. The electron is described by a ________ function, y.” 2. The square: y2 is the ___________________ of finding an electron at a certain position. The e- is most likely to be found where the "probability cloud" is ________________ 3. The electron is no longer thought to be located at a ________________ location, but may be ______________ . 4. The locations of highest probability correspond to the positions of the old________________________. _________ orbitals: _________ clouds Compare the 2 forces: 1. electromagnetic: Fe = • Is a force between two ___________________. • Attracts ________________ and repels _____________ • ___________________ ________range • Binds the ____ to the ___ within an atom and bonds_____________ to other ____________ 2. strong nuclear: Fsn • Is a force between two _________________ • Always________________, even between_____________ • _______________ force, but very ______________range • Holds the ____________________together Ex: In a ____________ n =_____________ nucleus (___________): p =___________ A close up of the 2 p: Fsn ________________ > Fe ___________________ The _________________ wins _____________nucleus In addition, the ________________are also attracted to the _______________ and to ________________ by the Fsn, and they have ________ Fe repulsion. Ex: In a ____________ nucleus (___________): 1 2 A close up of protons 1 and 2: 1 2 The _______________ Fe is ______ the Fe in small nuclei. BUT ______________Fsn is _____ the Fsn in small nuclei. ____________wins nucleus __________ and _________ For bigger nuclei: # of n _____ # of p. Why? The n’s provide extra Fsn _____________w/o Fe ___________. The existence of the ______________force means that there is an energy _____________ the nucleus called the _______________ energy. __________________discovered that this energy results in nuclei having more ____________ : The _______________________ of Mass and Energy Ex. If 5.0 x 10-3 kg of mass is totally converted to energy, how much energy will result? Notes: 1. If any object with ____________is converted completely into pure ____________ , it will release a total of ________ joules. Think of mass as _________________ energy. 2. The term _______ is simply a ______________________ between mass m and energy E. The mass is not moving at the ________________________ ! 3. What will the graph E shown at right look like? What quantity does the slope represent? m Ex 1: ____________ splitting __________ nuclei into______________ ones used in __________________________ after: before: n10 Ba14256 + Kr9136 + 3n10 + U23592 mass: = charge: = Is charge conserved? Is mass conserved? YES: The # of nucleons (n and p) is __________________. NO: The nucleons in Ba and Kr are ________________!!! n10 + U23592 Ba14256 + Kr9136 + 3n1o _________mass! ____________mass! The “missing” mass became _____________ ( E = mc2) in the form of _______ of Ba, Kr, n and _________________. This energy can be used 1/ _____________________________ in a ____________________ or 2/ ________________________ in an _______________________ . Chain reaction - _______________________________________ _______________________________________________________ ________________– used to ____________the reaction by ____________neutrons Ex 2: _____________: combining ____________nuclei into _____________ ones powers _________________ and__________________ after: before: H21 + He32 + n10 H21 mass = charge = Is charge conserved? Is mass conserved? YES: The # of nucleons (n and p) is __________________. NO: The nucleons in He32 and n10 are ________________!!! H21 + H21 _________mass! He32 + n10 ____________mass! The “missing” mass became _____________ ( E = mc2) in the form of _______ of He and n and _________________. The # of fusion power plants = ____ because it is difficult to get the _______________ close enough so that the _________________ attraction > electric _________________ . 3. _________ production: a gamma ray _____________ gets “tickled” as it passes a nucleus. Its ____________ becomes a _____________ and _________________ pair after: before: g-ray nucleus nucleus + The nucleus acts like a _________________ . The e+ is a _______________: the antiparticle of the e same ____________ as the e opposite ____________of the e- a. Compare the charge q before and after: = + charge _______________________ . b. Compare the mass before and after: = = + mass _______________________ . c. Compare "mass-energy" before and after: = + mass-energy _______________________ as long as Eph has an energy at least equal to _________________ Ex. Calculate the energy of the photon that is needed to produce an electron and positron pair. What is the frequency of the photon? ________________________ is ALWAYS conserved, even when _______________ is not. This is because mass can be converted to ________________ and vice versa, but neither __________nor ____________ can be destroyed. Ex: Is momentum p conserved? after: before: Rewrite these as: = Momentum p is _____________________________ . Ex: Could a g-ray produce two electrons? g charge: ? = e- e- + + _________________ b/c charge _____________conserved. In sum: 1. Momentum is _____________________ conserved. 2. Charge is _________________________ conserved. 3. Mass is ___________________________ conserved. 4. Energy is _________________________ conserved. 5. Mass-energy is ____________________ conserved. Numbers ___ and ___ are ___________ conserved when _______________ objects are involved. 4. Pair ______________________: matter and antimatter combine to form pure _________________ (photons). after: before: + a. Compare the charge q before and after: + = + charge _______________________ . b. Compare the mass before and after: + = = + mass _______________________ . c. Compare "mass-energy" before and after: + = + = mass-energy _______________________ as long as Eph has an energy at least equal to ____________ The idea behind particle accelerators (atom_____________): ________ particles + high __________: _______ particles because ________ The more the ________________ given to the old particles, the more _________________ of the new ones by E = ______. Ex: Early particle accelerators used _______________ generators: high _______________ work done on a charge q: W= Ex: How much KE will a proton gain when it is accelerated through a potential difference of 300,000 V? W= W= W= Ex: An example of a modern particle accelerator is the_____________________ . The _______________ field accelerates the particle. The ______________ field is ____________________ to v, so it only causes the particle to ___________________________ . As accelerators with higher and higher _____________ were built, particles with bigger and bigger ____________were discovered. There seemed to be no _____________ to the________________ of newly discovered particles. _____________________ _____________________ Finally, the _________________________ was worked out in the _______________ . It explained how all particles with mass are made up of ________________ fundamental particles and their _________________________ . The Standard Model: All matter (or antimatter) is made up of ___________or combinations of____________. _______ _______ __________________ increasing____________________ Neutrinos have _______ _____ mass. • Lepton means________________________ • Leptons all have charge _______or__________________ • Their antiparticles are charged __________________ • They occur____________________—they do not ___________________________________________. increasing __________________ • Quarks all have charge _________or ___________ • Their antiparticles are charged _________ or_________ • They ___________________by themselves because you cannot have a particle with a_________________________. • They occur in groups of _____________________ particles made from ___________ “bary-” means _______ masses Must be all __________ or all_____________ “mes-” means _________ masses Ex. A certain particle is made up of 3 quarks: 2 ________ quarks and 1 _____________ quark. What is the total charge of the particle? u: Add up the charges: u: d: Is this a baryon, a meson or a lepton? This particle is also known as a________________ Ex. A certain particle is made up of 2 quarks: 1 ____ quark and 1 __________ quark. What is the total charge of the particle? Add up the charges: u: d: Is this a baryon, a meson or a lepton? This particle is also known as a ______________________ Ex. A certain particle is made up of 3 quarks: 1 _____ quark and 2 ________ d d u quarks. What is the total charge of the particle? u: Add up the charges: d: d: Is this a baryon, a meson or a lepton? This particle is also known as a_____________________ Ex. A certain particle is made up of u 3 quarks: 2 ________________ quarks and 1 _________________ quark. u d What is the total charge of the particle? u: Add up the charges: u: d: Compare this one: u u d to: u u d The left-hand particle is an _______________________ . It is an example of ___________________ . It has the __________ mass as the proton, but the _________________ charge. Determine the charge and type of each particle. quark content s d total charge name u d s b b u d s d d u u type s The total charge must be ____________________________ The Fundamental __________________ of Nature: force strong nuclear electromagnetic weak gravitational range relative strength what it controls Ex: How can gravity hold Earth to the Sun if it is the weakest force? 1. Earth and Sun have a lot of ______________ 2. Earth and Sun are _________________ , so the __________________________ force is not important. 1. Earth and Sun are_______________ , so the ________________________ forces are not important. Ex: The total amount of mass-energy in the universe is: ordinary matter: ______% (baryons and leptons) dark matter: ______% (unknown) dark energy: ______% (unknown) Conservation Laws: Total before =________________ 1. _____________________ is always conserved. = 2. In the absence of_______________ , ________________ is always conserved. = 3. In the absence of________________, ________________ is always conserved. Classical physics: = = Modern physics: =