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Revolutions in Modern Physics - Leaderboard
Revolutions in Modern Physics - Details
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51 questions
| 🇬🇧 | 🇬🇧 |
| What are the three families of elementary particles? | Quarks, Leptons and Gauge Bosons |
| What are the positively charged quarks called? | Up, Charm and Top |
| What are the negatively charged quarks called? | Down, Strange and Bottom |
| What are the neutrally charged leptons called? | Electron neutrino, muon neutrino and tau neutrino |
| What are the negatively charged leptons called? | Electron, muon, tau |
| What are the gauge bosons called and what are their charges? | W Boson (±), Z Boson (neutral), Photon (neutron), Gluon (neutron). |
| Quark configuration of a proton? | Up, up, down |
| Quark configuration of a neutron? | Up, down, down |
| What are quarks? | An elementary particle and a fundamental part of matter. |
| What are hadrons? | Quarks held together by the strong nuclear force. Mesons are hadrons with 2 quarks. Baryons are hadrons with 3+ quarks |
| What are leptons? | Elementary particles that respond only to the electromagnetic force, weak force, and gravitational force |
| Which force do gluons mediate? | Strong Nuclear Force |
| What are elementary particles? | Things which are not composed of any other particles and cannot be subdivided. |
| What are the fundamental forces in order from strongest to weakest? | Strong Nuclear Force, Electromagnetic Force, Weak Nuclear Force, Gravity |
| What is Young's Double Slit Experiment? | Young split a beam of sunlight to produce two coherent beams (waves with the same frequency, amplitude and in-phase with each other) by creating a double slit. The light passes through onto a screen. Monochromatic light diffracted into coherent circular waves and interacted to form constructive interference (antinodal - bright fringes of light) and destructive interference (nodal - dark fringes) |
| What is Newton's particle theory? | Light should have passed through the slits to produce two bright lines or bands on the screen |
| What is black body radiation? | An object which absorbs the entire electromagnetic spectrum releases radiation but does not reflect any. |
| What is Wien's displacement law? | Λ max = b/T λ max is the peak wavelength b is the constant of proportionality T is the temperature Making an object hotter produces more radiation across the spectrum |
| What is wave-particle duality? | Wave-particle duality states that every particle or quantum entity may be partly described in terms not only of particles, but also of waves |
| What is the photoelectric effect? | When light shines on a metal, electrons can be ejected from the surface of the metal in a phenomenon known as the photoelectric effect. |
| Bohr | Jkdjf |
| What are the fundamental forces in order from strongest to weakest? | Strong Nuclear Force, Electromagnetic Force, Weak Nuclear Force, Gravity |
| What are elementary particles? | Things which are not composed of any other particles and cannot be subdivided. |
| What are the three families of elementary particles? | Quarks, Leptons and Gauge Bosons |
| What are the positively charged quarks called? | Up, Charm and Top |
| What are the negatively charged quarks called? | Down, Strange and Bottom |
| What are the neutrally charged leptons called? | Electron neutrino, muon neutrino and tau neutrino |
| What are the negatively charged leptons called? | Electron, muon, tau |
| What are the gauge bosons called and what are their charges? | W Boson (±), Z Boson (neutral), Photon (neutral), Gluon (neutral) |
| Quark configuration of a proton? | Up, up, down |
| Quark configuration of a neutron? | Up, down, down |
| What are quarks? | An elementary particle and a fundamental part of matter. |
| What are hadrons? | Quarks held together by the strong nuclear force. Mesons are hadrons with 2 quarks. Baryons are hadrons with 3+ quarks |
| What are leptons? | Elementary particles that respond only to the electromagnetic force, weak force, and gravitational force |
| Which force do gluons mediate? | Strong Nuclear Force |
| What are the problems with Newtonian physics? | - Light appeared to be a wave, but the medium for its propagation was undetectable - The equations describing electricity and magnetism were inconsistent with Newton's descriptions of space and time |
| What are the 2 postulates of special relativity? | 1. The relativity principle: the laws of physics have the same form in all inertial reference frames 2. Constancy of 'c': light propogates through empty space at c no matter the observer or speed of the source. |
| Define frame of reference | - Frame of reference is an arbitrary set of axes with reference to which the position or motion of something is described, or physical laws are formulated |
| How can we ascertain relative motion? | Velocity A relative to B = velocity A relative to stationary observer - velocity B relative to stationary observer |
| Recall 2 frames of reference | - Inertial frame of reference: non-accelerating frame of reference in which Newton's laws of motion hold (Are stationary or moving at a constant velocity) e.g. at rest on Earth, in a car at constant velocity - Non-inertial frame of reference are accelerating e.g. Accelerating upwards in an elevator, going around a corner |
| Explain simultaneity | - Simultaneity is the relation between two events assumed to be happening at the same time in a frame of reference - Relativity of simultaneity states that events that are simultaneous in one frame of reference are not necessarily simultaneous in another frame of reference, even if both frames are inertial |
| Why can't objects travel at the speed of light? | It's impossible to accelerate any material object up to the speed of light because it would take an infinite amount of energy to do so. |
| What is a Lepton number? | A conserved quantum number representing the difference between the number of leptons and antileptons in an elementary particle reaction. L = number of leptons - number of antileptons |
| What is a Baryon number? | A strictly conserved additive quantum number of a system. Stays the same before and after the reaction. |
| Describe an Electron-Electron particle interaction. | As an electron approaches another electron, they move closer. The electrostatic repulsion between them gets stronger and stronger until they exchange a photon (electromagnetic force carrier), which pushes each electron away from each other. |
| Describe an Electron-Positron particle interaction in Bhahba Scattering. | "Time reversed" arrow for positron, however it is approaching electron as the lines get closer. At the moment of interaction, they exchange a virtual photon and scatter off each other with velocities changed. |
| Describe an Electron-Positron particle annihilation. | Electron and positron approach each other and annihilate each other, forming a photon. The photon's energy creates a new electron-positron pair. |
| Describe beta minus (β−) decay. | A nucleus emits a high-energy electron (beta particle) and an antineutrino. This decay occurs when there are too many neutrons in the nucleus, and one of the neutrons decays into a proton, releasing an electron and an antineutrino. |
| Which particle interaction is this? | Electron-Electron |
| Which particle interaction is this? | Bhabha Scattering - Electron-Positron |
| Which particle interaction is this? | Annihilation - Electron-Positron |
| Which particle interaction is this? | Beta minus (β−) decay |
| Describe Rutherford's model of the atom | Rutherford expected alpha particles to pass right through the (plum pudding) atom, but huge deflections were found. From this, he concluded that: - The atom is mostly empty space with a tiny, very dense postively charged nucleus surrounded by negatively charged electrons - Nearly 100% of the atom's mass is contained in the nucleus - The number of electrons = number of positive charges - The nucleus is 100 000 times smaller than the atom |
| What were the limitations of Rutherford's model of the atom | - Rutherford's model did not account for the electromagnetic radiation that would be emitted by electrons revolving in circular paths, leading to the instability of atoms. - The model failed to explain the observed emission spectra, which displayed specific wavelengths of light instead of a continuous spectrum. |
| Describe the Bohr model of the atom and how it addresses the limitation of Rutherford's model | Electrons in an atom exist in stationary states - They do not emit energy while orbiting the nucleus Transitions between stationary states absorbs or emits electromagnetic radiation (photons) - Energy of the photon is given by Δ E = hf - If the atom absorbs too much energy, the outermost electron will be removed. This is the ionisation energy Angular momentum of a stationary electron is quantised - Angular momentum states that for circular motion, the momentum of a particle in which the velocity vector points along the radius of the circular path and is equal to mvr - Electrons must orbit at a fixed radii |