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Description
Flashcards by Malachy Moran-Tun, updated more than 1 year ago
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Created by Malachy Moran-Tun
about 4 years ago
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| Question | Answer |
| What Equation Relates Speed, Distance and Time? | Speed = Distance ÷ Time or Distance = Speed * Time or Time = Distance ÷ Speed |
| What is Newton's First Law? | > Resultant force is needed to make something start moving, speed up, or slow down > Anything moving at a constant velocity has a resultant force of 0 (the forces are balanced) |
| What is Newton's Second Law? | > Acceleration is proportional to the resultant force > F = m × a |
| Label the Parts of the Velocity-Time Graph | |
| What is Ultrasound? | Sound with Frequencies above 20,000 Hz (above Human Range of Hearing) |
| Fill in the Blank: Ultrasound Waves get ________ ________ at Boundaries | Ultrasound Waves get PARTIALLY REFLECTED at Boundaries |
| How can the Partial Reflection of Ultrasound be Useful? | Measure how far away the boundary is |
| What are some Examples of the Uses of Ultrasound? | > Ultrasound Imaging > Sonar > probably other stuff idk |
| What Equation links Distance, Wavespeed and Time? | Distance (m) = Wavespeed (m/s) × Time (s) or v = x ÷ t or t = x ÷ v |
| What is a Convex Lens? | > Converging lens > Bulges outwards in the middle > Causes parallel rays of light to be brought together > Principal focus is where the rays hitting the lens all meet |
| What Type of Image do Convex Lenses Form? | Real Images |
| How do you Draw a Ray Diagram for a Convex Lens? | > Pick a point on the top of the object > Draw a ray going from the object to the lens parallel to the axis > Draw another ray from the top to the middle of the lens > The top parallel (incident) ray is refracted through the focal point > The pay passing through the middle does not bend |
| Fill in the Blank: Electrons can be ______ to Higher _______ _______ | Electrons can be EXCITED to Higher ENERGY LEVELS |
| How does an Inner Electron Move Up to a Higher Energy Level / Shell? | Absorbs Electromagnetic Radiation with the Right Amount of Energy |
| What Happens to an Excited Electron after it Moves Up to a Higher Energy Level? | Quickly Falls Back into its Original Energy Level. This Emits the Same Amount of Energy it Absorbed |
| What is Half-Life? | A game that can't count to 3 (damnit valve) or The average time taken for the number of radioactive nuclei of an isotope to halve or The time taken for the activity to halve |
| How Dangerous are Sources with a Short Half-Life? | Very: they emit an extremely high amount of radiation initially. However, after the become safer |
| How Dangerous are Sources with a Long Half-Life? | Not as dramatically dangerous as short, however, nearby areas are exposed to radiation for millions of years, so they're also quite dangerous |
| How does Electromagnetic Radiation change Temperatures? | > Power Emitted > Absorbed - temperature falls > Power Emitted < Absorbed - temperature rise > Power Emitted = Absorbed - temperature stays constant |
| What is the Life-Cycle of a Star? | 1. Nebula 2. Protostar 3. Main Sequence Star Then either > Red Supergiant > Supernova > Neutron Star / Black Hole or > Red Giant > White Dwarf (check revision guide page for easy diagram) |
| What is a Nebula? | A cloud of dust and gas which will form into a star |
| How does a Nebula turn into a Protostar and then a Main Sequence Star? | > Force of gravity pulls the dust together > This forms a protostar > Temperature rise causes the protostar to get denser > When the temperature gets high enough (a cool 10,000,000°C approx.), nuclear fusion allows the formation of helium nuclei > This releases a huge amount of energy, keeping the core hot - it is now a main sequence star |
| Why are Main Sequence Stars Stable? | > Outward pressure caused by the thermal expansion (energy produced by nuclear fusion that tries to expand the star) is balanced with the force of gravity pulling inwards > Typically, main sequence stars can last several billion years > The heavier the star, the shorter its time on main sequence |
| How do Main Sequence Stars turn into Red (Super)Giants? | > Hydrogen in thee core runs out > Force due to gravity becomes larger than thermal expansion > Core of the star is compressed > Until it is sense and hot enough that the energy released makes the outer layers of the star expand > It is red since the surface cools |
| How does a Red Giant become a White Dwarf? | > Similar sized star to the Sun > Becomes unstable and ejects its outer layers > Leaves behind a hot, dense, solid core |
| How does a Red Supergiant become a Supernova? | > Big stars > Undergo nuclear fusion to make heavier elements > Expand and contracts several times as the balance between thermal expansion and gravity frantically shifts > Eventually, the star explodes into a supernova |
| How does a Supernova become a Neutron Star or Black Hole? | > Throws outer layers of dust and gas into space > Leaving a very dense core called a neutron star > If the star is massive enough, it will collapse and become a black hole |
| What is the Big Bang Theory? | > An American Sitcom with Only One Joke or > All Matter in the Universe initially occupied a Very Small Space > It was Dense and approx. a KJGHPILLION degrees (Kelvin obviously) > It then Exploded and started Expanding > There is a Finite Age for the Universe |
| How is Cosmic Microwave Background Radiation Evidence for the Big Bang? | The Radiation suggests the Universe was once much Hotter and Denser, so it must have had an initial beginning. |
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