physics module 7 dba

Georges-Heni Lemaitre

-proposed that the universe began as a dense, hot singularity that experienced a rapid expansion. He called this the "hypothesis of the primeval atom." -hypothesis was based on Einstein's Theory of Special Relativity and the red glow he detected in galaxies, which were a Doppler Shift of the light radiated from the galaxies. -universe was expanding and galaxies were moving away -entire universe was once a "singularity"—one dense, hot mass -cosmic egg

The equation for this wave is: λ = h/p

-λ = wavelength, h= is a physical constant called Planck's constant (h = 6.63 E−34 J*s or h = 4.14 E−15 eV*s). p= momentum of the object or p=mv (remember momentum is mv). -A body of large mass and ordinary speed has such a small wavelength that interference and diffraction are negligible, but smaller particles moving at high speeds produce appreciable diffraction patterns.

Dalton's Atomic Theory

1) elements are composed of atoms. 2) atoms of the same element are identical but differ from other elements. 3) elements can mix together 4) atoms only change when mixed with other elements

1. proton 2. neutron 3. gluon

1. A proton is a hadron, and it consists of three quarks: u, u, and d. 2. A neutron is also a hadron, and it consists of quarks u, d, and d. 3. In the quark model of a proton and neutron, three quarks are held together by gluons. The gluon is a carrier of the strong nuclear force that confines the quarks.

1. hadrons 2. gluons 3. Quarks

1. All particles made of quarks are called hadrons. A proton is a hadron, and it consists of three quarks: u, u, and d. A neutron is also a hadron, and it consists of quarks u, d, and d. 2. The gluon is a carrier of the strong nuclear force that confines the quarks. 3. A quark is a type of elementary particle and a fundamental constituent of matter.

Transmutations(topic) 1. Uranium—Alpha Decay 2. Thorium—Beta Decay

- The changing of one element into another by radioactive decay 1. Radioactive uranium-238 goes through alpha decay, producing an alpha particle (made of two protons and two neutrons) and leaving behind an atom of thorium-234. 2. When the thorium-234 decays, it produces a beta particle (an electron) and leaves behind an atom of protactinium-234.

Big Band Theory

- states that all galaxies originated from one huge mass of densely packed matter - three testable phenomena Expanding universe Sea of background radiation An abundance of light elements

electromagnetic spectrum

-all of the frequencies or wavelengths of electromagnetic radiation -radio, micro, infrared, visible, UV, x, gamma -energy found by taking the frequency of each wave and multiplying it by Planck's constant

quarks

-fundamental particles with quarks. There are six known quarks: up (u) and down (d), charm (c) and strange (s), and top (t) and bottom (b). -all particles made of quarks are hadrons -controlled by the strong nuclear force

1. ionic compound 2. molecular (covalent) compound

1. An ionic compound is formed when an electron from one atom is lost to another and the two ions form an ionic bond. They are held together by their opposite electrical charges, but they remain as individual ions. 2. A molecular (covalent) compound, or molecule, forms when atoms share some of their electrons in a covalent bond. The two atoms, often both nonmetals, overlap their valence energy levels and are held together by a mutual attraction to the shared electrons.

1. mass conversion equation 2. photons

1. e=mc^2; when a particle and its antiparticle encounter each other, they annihilate each other, and their mass is converted into energy E is the energy, m is the mass, c is the speed of light in a vacuum 2. Photons are another fundamental particle. Photons are bundles or quanta of light. Light transfers energy but just how this energy transfer takes place gave rise to one of the greatest conundrums in physics. Photons have no mass, but they have momentum and they have energy.

Special Theory of Relativity

Einstein's theory that no particle of matter can move faster than the speed of light and that motion can be measured only relative to a particular observer - Einstein's first postulate: All the laws of physics are the same in all inertial frames of reference. - Einstein's second postulate: The speed of light, c, in free space is the same as any uniformly moving observer. Remember: The speed of light will always be 3.0 × 108 m/s (3 E8 m/s), no matter what

photoelectric effect equation

Incoming Energy of Photon → Energy Needed to Eject a Photoelectron + Kinetic Energy of Ejected Photoelectron

From this, we can calculate the kinetic energy of the most energetic photoelectron using this equation:

KEmax = Voq Vo is the stopping potential, q is the charge of the photoelectron.

subatomic

Smaller than an atom. The proton, neutron, and electron are subatomic particles

standard model theory

The Standard Model is a theory in particle physics that addresses three of the four known forces in Nature: electromagnetic force, weak nuclear force, and strong nuclear force. There are six known quarks: up (u) and down (d), charm (c) and strange (s), and top (t) and bottom (b).

photoelectric effect

The emission of electrons from a material when the light of certain frequencies shines on the surface of the material. For solids, electrons are only liberated when the wavelength of the illumination is shorter than a certain value (called the photoelectric threshold).

George Gamow

predicted if the big bang was correct there would be observable microwave background radiation after the hot universe cooled down. The wavelengths would correlate to the expected temperature of approximately 3 Kelvin.

work function

the amount of energy needed to dislodge an electron from the surface of a material

strong nuclear force

the attractive force that binds protons and neutrons together in the nucleus

The Standard Model

the current theory of particle physics that deals with elementary particles (quarks, electrons, etc.) and their interactions.

expanding universe

the idea that the space between galaxies or clusters of galaxies is growing with time. Hubble's Law: v = (Ho)(d) v is the recessional velocity of the galaxy in km/s measured using the Doppler Effect d is the distance to the galaxy in Mpc (1 megaparsec = 3E6 light-years), Ho is the Hubble constant

Quantum Mechanical Model

the modern description of the behavior of electrons in atoms it adds to our understanding of atomic structure and electron behavior.

half-life

the time it takes for the radioactivity level of an isotope to decrease to half its orginial value equation: The equation for half-life is: m f = mi/2n mf is the final amount of the radioactive material mi is the initial amount of the radioactive material n is the number of half-life

increase the potential of the battery, eventually you will oppose the movement of the photoelectrons

when the photoelectrons no longer have enough energy to leave the photo emissive material, the current will be zero.

law of multiple proportions

whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers

types of beta decay

1. Beta Negative Decay ( −) represents a high speed electron, with an A-number of zero and a Z-number of −1, which has been released from the nucleus when a neutron decays into a proton, an electron, and an antineutrino by way of the weak force 2. Beta Positive Decay (+) - represents an anti-electron which is called a positron, with an A-number of zero and a Z-number of +1, which has been released from the nucleus when a proton decays into a neutron, a positron, and a neutrino by way of the weak force 3. Electron Capture, or K-Shell Capture, is when an electron is absorbed into the nucleus and joins with a proton to form a neutron. A neutrino is also produced.

Equations for the photoelectric effect

1. E = hf How is the relationship between frequency and the energy of a photon expressed? (through the energy of a photon equation) 2. Wo = hfo The kinetic energy of the ejected photoelectron is equal to the difference between the incoming energy of the photon minus the work function. 3. KE = hf − hfo The ammeter measures the current of the circuit. As you increase the potential of the battery, eventually you will oppose the movement of the photoelectrons; when the photoelectrons no longer have enough energy to leave the photoemissive material, the current will be zero.

principal observations that light travels as photons

1. Electrons are emitted only when the frequency of the light is above some threshold value, no matter how intense the light. 2. The maximum KE of the ejected photoelectrons depends on the frequency of the light, not the intensity of the light. As the intensity of light increases, the number of photoelectrons ejected will increase only if the frequency is above the threshold frequency.3. The photoelectrons are ejected almost at once when the light strikes.

1. how is light like waves 2. how is light like particles 3. the types of radiation decay and a fact about each 4. what are ionic and covalent bonds 5. description about the modern atomic model

1. Light behaves as a wave - it undergoes reflection, refraction, and diffraction just like any wave would. 2. particle: when it interacts with matter (evidence = photoelectric effect/light emission spectra) 3. alpha decay, beta decay, and gamma decay 4. An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. (fact: Ionic bond, also called an electrovalent bond) A (covalent) compound, or molecule, forms when atoms share some of their electrons in a covalent bond. (fact: covalent bonds often form between atoms) 5. it is based on the modern atomic theory, which states that all matter is composed of atoms. Atoms themselves are composed of protons, neutrons, and electrons.

1. physical changes 2. chemical changes

1. Physical changes are changes that do not result in the formation of a new substance. The shape, form, or appearance of a substance may have changed, but the substance is still the same 2. Chemical changes are usually referred to as chemical reactions. Chemical changes always produce new substances with properties that are typically very different from those of the reactants.

1. Plank's Constant 2. Planck's constant

1. Planck's constant (E = hf) 2. 6.626 x 10^-34 a number used to calculate the radiant energy (E) absorbed or emitted by a body based on the frequency of radiation

sources of electromagnetic radiation

1. The sun emits small amounts of gamma radiation and other kinds of harmful radiation. 2. Rocks and minerals, including those found in brick and concrete, contain trace amounts of uranium.

Photoelectric Effect Graph

1. The x-axis is the incoming frequency of light. 2. The y-axis is the maximum amount of kinetic energy a photoelectron will have if it is ejected with a certain frequency. This energy is measured in the convenient unit of energy, the electron volt (eV). One eV is equal to 1.6 E−19 J of energy. 3. The y-intercept is the work function (Wo). 4. The x-intercept is the threshold frequency (fo). 5. The slope is the physical constant Planck's constant. This means the slope of the graph will be numerically the same as the x-intercept and y-intercept change.

1. ion 2. isotope 3. group 4. period

1. a charged atom 2. atoms of the same element that have different numbers of neutrons 3. vertical column 4. horizontal column

1. electromagnetic force 2. weak nuclear force 3. strong nuclear force

1. a force associated with charged particles, which has two aspects, electric force and magnetic force 2. a powerful attractive force that acts over a short range 3. the powerful attractive force that binds protons and neutrons together in the nucleus

types of radiation decay

1. alpha (α) - Alpha radiation is made up of a stream of alpha particles. Alpha particles are made up of two protons and two neutrons released from the nucleus of the radioactive atom. 2. beta (β) - Beta radiation is made up of a stream of beta particles. Beta particles are fast-moving electrons released from a nucleus when a neutron breaks apart into one proton and one electron. 3. gamma (γ) - Gamma radiation can be given off during different types of nuclear decay. Gamma rays are a form of electromagnetic waves with a very high frequency and greater energy than ultraviolet light or X-rays.

1. antiparticle 2. antimatter 3. antiproton 4. anti-quarks 5. positron

1. an antimatter particle with the same mass and opposite charge as a corresponding matter particle EX: positron is the anti-electron or positively charged electron 2. molecules formed by atoms consisting of antiprotons, antineutrons, and positrons. Stable antimatter does not appear to exist in our universe. 3. the negatively charged antiparticle of a proton anti-quarks are ū ū and d.4. anti-quarks: ū, ū, and ƌ. 5. a particle with the mass of an electron but a positive charge (uud)

1. antiparticle 2. antiproton

1. an antimatter particle with the same mass and opposite charge as a corresponding matter particle. EX: positron is the anti-electron or positively charged electron 2. Antiparticle of a proton; a negatively charged proton. The antiproton consists of anti-quarks: ū, ū, and ƌ.

1. JJ Thompson 2. Rutherford 3. Bohr 4. Chadwick

1. cathode ray experiment, discovered electrons, named them corpuscles, known for plum pudding model 2. gold foil experiment, found nucleus 3. different energy levels for electrons 4. isolated neutrons

1. the gamma factor (y) 2. time dilation 3. length contraction

1. is a value that shows the amount of change in time, length, and mass due to the speed of an object. This change can be an increase or a decrease depending on the quantity. y = 1 /(√1−(v^2/c^2)) v is the velocity of the object c is the velocity of light (3 E8 m/s) 2. Clocks moving relative to an observer are measured by that observer to run more slowly as compared to clocks at rest Δt=Δt0y v is the relative speed between the observer who measures Δt0 Δt the change in time the observer measures 3. The length of an object moving relative to an observer is measured to be shorter than when it is at rest. L=L0/y v is the relative speed between the observer who measures L0 L the length the observer measures

1. radiation 2. radioactivity

1. is the emission of energy as electromagnetic waves 2. is the emission of radiation caused by the spontaneous disintegration of atomic nuclei

1. atomic mass 2. atomic number (Z number) 3. atomic mass number 4. C-14 (carbon) 5. (14/6)C

1. the average mass of all the isotopes of an element, or mass of an atom 2. number of protons 3. number of protons and neturons 4. 14=mass number 5. 14= mass number, 6= atomic number

1. How have the contributions of scientists changed our understanding of atoms 2. How are subatomic particles used to understand properties of elements 3. how does the periodic table help us determine subatomic particles? 4. How do a finite number of elements form an infinite number of compounds through changes in matter? 5. How do our understandings of light quanta and wave behavior give us a full understanding of the nature of light? 6. How does the standard quantum model give us a greater understanding of atoms? 7. How do we quantify interactions among subatomic and fundamental particles? 8. What are the differences between the types of radiation and how do radioactive elements help us understand the world? 9. How does our understanding of light give us knowledge about the origin of the universe and how energy and matter interact?

1. the contributions of scientists changed our understanding of atoms by developing models of atoms such as daltons models and theories. 2. The number of protons determines an element's atomic number and is used to distinguish one element from another. 3. With the help of the periodic table of elements, we can calculate how many subatomic particles there are in a given atom. 4. ?? 5. Light behaves mainly like a wave but it can also be considered to consist of tiny packages of energy called photons. Photons carry a fixed amount of energy but have no mass. They also found that increasing the intensity of light increased the number of electrons ejected, but not their speed. 6. the current theory of particle physics that deals with elementary particles (quarks, electrons, etc.) and their interactions. 7. A typical atom consists of three subatomic particles: protons, neutrons, and electrons 8. alpha decay, beta decay, and gamma decay The radioactive elements uranium and plutonium are used in the generation of electricity in nuclear power plants. Small radioactive sources of particles are used in many home smoke detectors. These elements are also used in the production of nuclear weapons. 9. ??

1. mass defect 2. binding energy

1. the difference between the mass of an atom and the sum of the masses of its protons, neutrons, and electrons 2. the energy that holds a nucleus together, equal to the mass defect of the nucleus.

atomic theory

a theory that states that all matter is composed of tiny particles called atoms. 3 experiments that led to the understanding that atoms were made of smaller bits of matter and the important atomic discoveries 1. the discovery of electrons- Thomson hypothesized that these corpuscles were scattered within a positively charged atom, just like plums are mixed throughout plum pudding—hence the name of his model. 2. rutherford and the nucleus-Rutherford proposed that there must be something big and positively charged in the center of each gold atom to cause the radiation particles to do this. He named this center the nucleus of the atom. 3. bohr's orbital- Bohr proposed that electrons moved in specific orbits around a positive nucleus based on their energy level. He predicted there were many energy levels in which electrons could exist. They are not randomly scattered, as scientists first predicted.

The speed of light (in a vacuum) is the product of frequency times wavelength.

c = fλ

is light a wave or particle?

can be both or a wave of particles wave: when it travels through space (evidence = interference patterns) particle: when it interacts with matter (evidence = photoelectric effect/light emission spectra)

the podcast

it talked abouy concerns about cellphone safety and how excessive cellphone use might affect health and risk for brain tumors.

Fred Hoyle

labeled Lemaitre's hypothesis the "Big Bang" during a radio interview to distinguish it from his hypothesis of the universe, which he called the "Steady State."