2023 Paper 2 (17/01/2025) Flashcards
Internal Energy of Ideal Gas?
Total kinetic energy of particles
Momentum change of -2mc?
This is because the speed before and after is the same in an elastic collision. This produces the equation Δp (= p final – p initial) which makes “ -mc - mc = -2mc “
Frequency of collisions c / 2L?
In “ F = 1 / T “ the time for frequency of collisions is the time it takes for the particles to complete 2 lengths of the box. This means the speed equation re-arranged for “t” is: “ t = x / v “ otherwise “ t = 2L / C “. Putting this value of “t” in the frequency equation produces the desired equation of: “ F = c / 2L “
Use of Newton’s Second Law?
Newton’s 2nd Law is the rate of change of momentum of an object is directly proportional to the net force acting on it and occurs in the direction of the force. This means whenever a force is mentioned this law can be applied.
Radial Field Properties?
Field strength decreases with distance in an inverse square relationship. Always attractive in a radial field. Region in which a mass experiences force due to another mass. Field is conservative meaning any change in potential energy depends on the initial and final positions instead of the path. Field lines point to the centre of mass. Equipotential surfaces are spherical around the centre of mass. Gravitational force is a non-contact force.
Area under Gravitational Force against Height Graph?
On a graph where gravitational force is on the y-axis and height above the surface is on the x-axis. The area under the graph is equal to the change in potential energy and is the minimum energy used to get an object to a desired height from Earth’s surface
Distance between Earth and Sun?
At the edge of the solar system the distance between the Earth and Sun is roughly the same. So as the Earth has a smaller mass it produces less force than the sun due to the sun having a larger mass, this means its less important for calculation involving objects escaping the solar system.
Relationship when calculating using gravitational orbits?
The kinetic energy will be equal to the potential energy
Diagram of field equipotential lines?
Equipotential lines at uniform seperated distances indicate a weak field but when close together they indicate a strong field
Atom compared to electron passing through air?
The atoms are larger and have higher mass which leads to them being more efficient and consequently more ionising than electrons at ionising air. Due to being able to ionise the air more the atoms experience more collisions which means they lose more energy and momentum travelling through air compared to electron
Exponential relationship from graph?
y1 / y2 = y2 / y3 and if this is very close or the same it means the values on the other axis have an exponential relationship with these ones
Inverse Square Law from graph?
If the two values multiplied together with one square for 2 different cases are the same or very close it means they have an inverse square relationship
Comparing time taken for charging capacitors?
Have two separate equations with the different voltages divided by the EMF’s battery. Re-arrange to get each equation to equal their respective “t”. Then take the equation with the higher voltage involved and take its “t” value and minus it from the other equation. Then factorise to get RC and this will be the simplified value
Benefits of high energy electrons compared to alpha particles to estimate nuclear radii?
Using electrons can give greater resolutions since their wavelength can be made very small. Electrons can get closer to the nuclei as they don’t encounter electrostatic repulsion. Electrons have less recoil as their mass is smaller than that of the nucleus. Free electrons are easier to accelerate and receive energy as they have a higher charge to mass ratio. Electrons are easier to produce. Strong nuclear interaction is not involved meaning scattering distributions are easier to interpret. Using alpha particles only gives distance from the closest approach to radius.
How to show all nuclei have same density?
Sub in the nuclear radius formula to the density formula with volume expanded to that of a sphere. Then replace mass with the atomic number times the mass of the nucleon. Cancelling down removes both “A” values which means all nuclei have the same mass as all the values left in the equation are constant.
Why is constant of nuclear material only an approximate?
The mass is not exactly the nucleon number multiplied by the mass of a nucleon because this ignores binding energy. The volume equation assumes the nucleus is a perfect sphere which it’s not. The density equation that uses the nuclear radius formula implies density is uniform within the nucleus which isn’t true. Protons have slightly different masses to neutrons.
Benefits of slowing down neutrons during fission?
The Uranium fuel will be more likely to absorb the neutrons due to the change in thermal speed. Slow neutrons are less damaging and cause less fatigue to the structure of the reactor. Slow neutrons spend longer with fissionable material and increase the chance of causing fission. Slowing neutrons transfers heat energy to the moderator which makes heat easier to extract.
Small Nucleon Number as moderator?
Low nucleon number so less atomic mass material gives a greater reduction in speed and kinetic energy in a collision. Fewer collisions are needed because of the low atomic mass which means the moderator can be thinner.
What can lead to a value for absolute zero of temperature?
Charles’s Law
Escape Velocity Equation?
E = GMm / r
Geostationary Orbit trends?
Satellites orbit in the plane of the Earth’s equator. Satellite has the same angular velocity as any point on the Earths surface. It takes 24 hours to orbit the Earth
Gradient of magnetic flux against time graph?
The gradient of a magnetic flux against time graph is the EMF
Reason for radioactive waste being stored underground?
To protect workers from effects of gamma radiation from nuclides with a small decay constant
Which radiation measures thickness of aluminium sheet correctly?
Beta Minus
