OpenLLM-France/wikimedia huggingface dataset:
# A-level Physics (Advancing Physics)/Quarks

Quarks (pronounced like 'orcs' with a 'qu' on the front) are a subset of the fermions - they make up part of matter, most notably the nuclei of atoms. Quarks interact with all four of the fundamental forces: gravity, electromagnetism, and the weak and strong nuclear forces.

## Generations

There are four quarks in each of the three generations of fermions. The first contains the up quark ($u$), down quark ($d$), antiup quark (${\bar {u}}$) and antidown quark (${\bar {d}}$). The second generation contains the charm quark ($c$), strange quark ($s$), anticharm quark (${\bar {c}}$) and antistrange quark (${\bar {s}}$). The third generation contains the top quark ($t$), bottom quark ($b$), antitop quark (${\bar {t}}$) and antibottom quark (${\bar {b}}$).

## Charge

The up, charm and top quarks have a charge of +⅔e, and so their respective antiparticles have a charge of -⅔e. The down, strange and bottom quarks have a charge of -⅓e, and so their respective antiparticles have a charge of +⅓e.

## Hadrons

When quarks are combined, they form larger particles, which are not fundamental. These larger particles are known as hadrons and are held together by the strong nuclear force. There are two types of hadrons: baryons and mesons.

### Baryons

Baryons are hadrons which are made up of three quarks. The two most common baryons are the proton and the neutron. Protons are made up of two up quarks and one down quark, giving them a total charge of +1e. Neutrons are made up of one up quark and two down quarks, giving them net charge of 0.

### Mesons

Mesons are hadrons which are made up of a quark and an antiquark. For example, pions are made up of two first generation quarks - the π$^0$ is made up of either an up quark and an antiup quark, or a down quark and an antidown quark. The π$^+$ is made up of an up quark and an antidown quark (total charge +1e), and The π$^-$ is made up of a down quark and an antiup quark (total charge -1e).

## Questions

1. The Δ$^{++}$ baryon is made up of up quarks. What is its total charge?
2. The Δ$^-$ baryon has a total charge of -1e. Given that it is made up of only one type of first generation quark, what is this quark?
3. What is an antiproton made of? What is its charge?
4. A K+ meson is made of an up quark and an antistrange quark. What is its total charge?
5. Lambda (Λ) baryons are made up of an up quark, a down quark, and another quark (not an antiquark). The Λ$^0$ is neutral, and contains a second generation quark. What is this quark?
Worked Solutions
# A-level Physics (Advancing Physics)/Radioactive Emissions/Worked Solutions

You will need a periodic table.
1. Americium-241 is an α emitter. What element, and what isotope, is produced by this decay?
$_{95}^{241}Am\to \;_{a}^{b}?+\;_{2}^{4}\alpha$
b = 241 - 4 = 237
a = 95 - 2 = 93
So, $_{93}^{237}Np$ (Neptunium-237) is produced.
2. Iodine-129 is a β$^-$ emitter. What element, and what isotope, is produced by this decay?
$_{53}^{129}I\to \;_{a}^{b}?+\;_{-1}^{0}\beta ^{-}+\;_{0}^{0}{\bar {\nu }}$
b = 129
a = 53 + 1 = 54
So, $_{54}^{129}Xe$ (Xenon-129) is produced.
3. Gamma rays are used to kill microbes in food. Why doesn't the food become radioactive?
Gamma radiation only interacts with the electrons of the atom, not with the nucleus. Radioactivity is due to nuclear properties, not chemical properties.
4. Plutonium-244 decays by emitting an α particle. It does this twice, emits a β$^-$ particle, and then emits a further two α particles. The nucleus becomes a different element each time. What element is produced at the end?
$_{94}^{244}Pu\to \;_{a}^{b}?+\;4\;_{2}^{4}\alpha +\;_{-1}^{0}\beta ^{-}$
b = 244 - 16 = 228
a = 94 - 8 + 1 = 87
So, at the end of this decay chain, $_{87}^{228}Fr$ (Francium-228) is produced.
5. Carbon-11 changes into Boron-11 by a radioactive emission. What was emitted?
$_{6}^{11}C\to \;_{5}^{11}B+\;_{a}^{b}?$
b = 11 - 11 = 0
a = 6 - 5 = 1
So, a positron ($_{1}^{0}\beta ^{+}$) was emitted. However, in order for the lepton numbers to balance, a neutrino ($_{0}^{0}\nu$) must also be emitted.
6. Uranium-236 decays, following the equation:
$_{92}^{236}U\to \;_{90}^{232}Th+\;X$
Identify the particle X in this equation.
Solve these type of problems by applying the conservation laws: e.g. the decay must balance electric charge, nucleon number, proton number, lepton number etc. Nucleon number doesn't balance (236 = 232 + ?), so X must have a nucleon number of 4.
The Proton number does not balance either (92 = 90 + ?) therefore X must have 2 Protons.
Therefore it can be concluded that X is an alpha particle.
# A-level Physics (Advancing Physics)/Quarks/Worked Solutions

1. The Δ$^{++}$ baryon is made up of up quarks. What is its total charge?
Baryons are made of three quarks. 3 x +⅔ = +2e
2. The Δ$^-$ baryon has a total charge of -1e. Given that it is made up of only one type of first generation quark, what is this quark?
Three identical quarks must have a total charge of -1e, so one of these quarks has a charge of -⅓e. This is a down quark.
3. What is an antiproton made of? What is its charge?
${\bar {u}}{\bar {u}}{\bar {d}}$, total charge -1e.
4. A K+ meson is made of an up quark and an antistrange quark. What is its total charge?
⅔ + ⅓ = +1e
5. Lambda (Λ) baryons are made up of an up quark, a down quark, and another quark (not an antiquark). The Λ$^0$ is neutral, and contains a second generation quark. What is this quark?
0 = +⅔ - ⅓ + q
q = -⅓
The second generation quark with a charge of -⅓e is the strange quark.
# A-level Physics (Advancing Physics)/Radioactive Decay
## Decay Constant

We can model radioactive decay by assuming that the probability that any one nucleus out of N nuclei decays in any one second is a constant λ. λ is known as the decay constant, and is measured in s$^{−1}$ (technically the same as Hz, but it is a probability, not a frequency, so we use s$^{−1}$).

## Activity

As our N nuclei decay, the number of nuclei decreases. The activity of the N nuclei we have left is, on average, the probability that any one nucleus will decay per. unit time multiplied by the number of nuclei. If we have 200 nuclei, and the decay constant is 0.5, we would expect, on average, 100 nuclei to decay in one second. This rate would decreases as time goes by. This gives us the following formula for the activity A of a radioactive sample:
$A=-{\frac {dN}{dt}}=\lambda N$
Activity is always positive, and is measured in becquerels (Bq). It is easy to see that the rate of change of the number of nuclei is -A = -λN.

## Decay

The solution of the differential equation for activity given above is an exponential relationship:
$N=N_{0}e^{-\lambda t}$,
where N is the number of nuclei present at a time t, and N$_0$ is the number of nuclei present at time t=0. You can define t=0 to be any point in time you like, provided you are consistent. Since A = λN and therefore A$_0$ = λN$_0$:
$A=A_{0}e^{-\lambda t}$,
where A is the activity of the sample at a time t, and A$_0$ is the activity at time t=0.

## Questions

1 mole = 6.02 x 10$^{23}$ atoms
1u = 1.66 x 10$^{−27}$kg
1. Americium-241 has a decay constant of 5.07 x 10$^{−11}$s$^{−1}$. What is the activity of 1 mole of americium-241?
2. How many g of lead-212 (λ = 18.2μs$^{−1}$) are required to create an activity of 0.8 x 10$^{18}$Bq?
3. How long does it take for 2 kg of lead-212 to decay to 1.5 kg of lead-212?
4. Where does the missing 0.5 kg go?
5. Some americium-241 has an activity of 3kBq. What is its activity after 10 years?
6. This model of radioactive decay is similar to taking some dice, rolling them once per. second, and removing the dice which roll a one or a two. What is the decay constant of the dice?
7. If you started out with 10 dice, how many dice would you have left after 10s? What is the problem with this model of radioactive decay?
Worked Solutions
# A-level Physics (Advancing Physics)/Quantum Principles

There are two principles which you do not need to know for the exam, but may be helpful in understanding some of the concepts in the course.

## Heisenberg Uncertainty Principle

The Heisenberg uncertainty principle states that the momentum and position of an object are limited. Within a certain uncertainty, when we measure a quantum's position, it does not have a definite momentum. When we measure its momentum, it ceases to have a definite position. If we try and measure both, the uncertainty in both will be limited. If we let the uncertainty in our knowledge of momentum be Δp, and the uncertainty in our knowledge of position be Δx:
$\Delta x\Delta p={\frac {h}{4\pi }}$,
where h is Planck's constant (6.63 x 10$^{−34}$ Js). The Heisenberg uncertainty principle explains what happens when electrons occupy energy levels - within these levels, they are limited to a certain range of momentums and positions, but it is meaningless to say which exact momentum and position they occupy. If we measure the momentum with no uncertainty, then the uncertainty in position becomes infinite, and vice versa.

## Pauli Exclusion Principle

The Pauli exclusion principle states that no two fermions (a set of particles including the electron) may occupy the same quantum state as each other. In layman's inaccurate terms, this means that, although two such particles can be in the same place as each other, if they are, they will be moving at different velocities and so will shortly no longer be in the same place as each other.
This is why, for example, electrons appear to have 'shells' - there is only a limited number of quantum states that the electrons can occupy, so some have to occupy a different 'shell'. Also, without the Pauli exclusion principle, matter would collapse in on itself - the attractive forces between particles are greater than the repulsive forces. However, the moment they try and do this, then they must be moving at different velocities, and so no longer be collapsing in on each other.
# A-level Physics (Advancing Physics)/Radar and Triangulation/Worked Solutions

1. A radar pulse takes 8 minutes to travel to Venus and back. How far away is Venus at this time?
$2d=ct=3\times 10^{8}\times 8\times 60=1.44\times 10^{11}{\mbox{ m}}$
$d=1.44\times 10^{11}\times 0.5=7.2\times 10^{10}{\mbox{ m}}$
2. Why can't a radar pulse be used to measure the distance to the Sun?
It would be impossible to pick up the reflected signal due to all the other signals coming from the Sun. Also, the signal would almost certainly be absorbed anyway.
<<Added>> Regardless of (λ) wavelength, power density, or wavefront properties, the pulse would be absorbed with no reflection possible. Distances to pure energy sources are generally measured in terms of received light intensity, shifts of the light spectrum, and radio interferometry. The RF spectrum; and Laser (light) spectrum can be used to "listen" to radiation, but not bounce a pulse from an energy source having no true angle of incidence. Just as an observation, I will note that the sun can be seen on most radars either sunrise or sunset, usually when the sun is just above the horizon. But these receptions are unusable strobes (interference) and not a result of receiving a radar pulse from the sun. Radar technicians also use the sun as a "known" exact position to align the system to true north (and magnetic variations); this is called solar-boresighting and, again, only receives the radiation.
3. Radar is used to measure the velocity of a spacecraft travelling between the Earth and the Moon. Use the following data to measure this velocity:
| Pulse | Transmission Time | Reception Time |
| 1 | 3:26:45.31213 | 3:26:45.51213 |
| 2 | 3:26:46.32742 | 3:26:46.52785 |
First, calculate the distance of the spacecraft from the Earth at each time:
$d_{1}={\frac {c\Delta t_{1}}{2}}={\frac {3.0\times 10^{8}\times (45.51213-45.31213)}{2}}=30,000{\mbox{ km}}$
$d_{2}={\frac {c\Delta t_{2}}{2}}={\frac {3.0\times 10^{8}\times (46.52785-46.32742)}{2}}=30,064.5{\mbox{ km}}$
Next, calculate the distance the spacecraft has travelled between the two pulses:
$\Delta d=d_{2}-d_{1}=30,064.5-30,000=64.5{\mbox{ km}}$
Now, calculate the time elapsed between the transmission of the two pulses:
$\Delta t=t_{\beta }-t_{\alpha }=46.32742-45.31213=1.01529{\mbox{ s}}$
Finally, divide the distance the spacecraft has travelled between the two pulses by the time between the transmission of the two pulses, to give the average velocity of the spacecraft in that interval of time:
$v={\frac {\Delta d}{\Delta t}}={\frac {64.5}{1.01529}}\approx 63.5{\mbox{ kms}}^{-1}$
4. The angles between the horizontal and a star are measured at midnight on January 1 as 89.99980° and at midnight on June 1 as 89.99982°. How far away is the star?
$d={\frac {2r\tan {a}\tan {b}}{\tan {a}+\tan {b}}}={\frac {2\times 150\times 10^{9}\times \tan {89.9998}\tan {89.99982}}{\tan {89.9998}+\tan {89.99982}}}=4.52\times 10^{13}{\mbox{ km}}$
5. Why can't triangulation be used to measure the distance to another galaxy?
The difference between the two angles becomes so tiny that we don't have good enough equipment to measure it.
# A-level Physics (Advancing Physics)/Radioactive Decay/Worked Solutions

1 mole = 6.02 x 10$^{23}$ atoms
1u = 1.66 x 10$^{−27}$kg
1. Americium-241 has a decay constant of 5.07 x 10$^{−11}$s$^{−1}$. What is the activity of 1 mole of americium-241?
$A=\lambda N=5.07\times 10^{-11}\times 6.02\times 10^{23}=3.05\times 10^{13}{\mbox{ Bq}}$
This is why we only need very small samples for use in, for example, smoke detectors. In fact, safety considerations necessitate a small sample - otherwise we would all have cancer!
2. How many g of lead-212 (λ = 18.2μs$^{−1}$) are required to create an activity of 0.8 x 10$^{18}$Bq?
$N={\frac {A}{\lambda }}={\frac {0.8\times 10^{18}}{18.2\times 10^{-6}}}=4.40\times 10^{22}{\mbox{ nuclei}}=4.40\times 10^{22}\times 212\times 1.66\times 10^{-27}=15.5{\mbox{ g}}$
3. How long does it take for 2 kg of lead-212 to decay to 1.5 kg of lead-212?
Mass is proportional to the number of atoms, so:
$m=m_{0}e^{-\lambda t}$
${\frac {m}{m_{0}}}=e^{-\lambda t}$
${\frac {m_{0}}{m}}=e^{\lambda t}$
$\lambda t=\ln {\frac {m_{0}}{m}}$
$t={\frac {\ln {\frac {m_{0}}{m}}}{\lambda }}={\frac {\ln {\frac {2}{1.5}}}{18.2\times 10^{-6}}}=15807{\mbox{ s}}=4.39{\mbox{ hours}}$
4. Where does the missing 0.5 kg go?
It becomes another isotope - in this case, mercury-208. Some also becomes alpha particles.
5. Some americium-241 has an activity of 3kBq. What is its activity after 10 years?
$A=A_{0}e^{-\lambda t}=3000\times e^{-5.07\times 10^{-11}\times 10\times 365.24\times 24\times 60\times 60}=2.952{\mbox{ kBq}}$
6. This model of radioactive decay is similar to taking some dice, rolling them once per. second, and removing the dice which roll a one or a two. What is the decay constant of the dice?
The decay constant is the probability of removing a die - λ = ⅓.
7. If you started out with 10 dice, how many dice would you have left after 10s? What is the problem with this model of radioactive decay?
$N=N_{0}e^{-\lambda t}=10\times e^{-{\frac {1}{3}}\times 10}=0.357{\mbox{ dice}}$
Obviously, you can't have 0.357 dice. The problem with this model of radioactive decay is that, once you have sufficiently few nuclei, the decay ceases to be continuous. As time passes, the pattern becomes relatively more random. The model also says that the number of nuclei will always decrease. In reality, since there can only be an integer number of nuclei, there will eventually come a point when there are no nuclei left.
# Adventist Youth Honors Answer Book/Stars/Big Dipper, Cassiopeia, and the North Star
## Northern Hemisphere

    These stars and constellations can be seen from anywhere north of the tropics in the Northern Hemisphere (they are more difficult to see in the tropics, and the North Star cannot be seen at all from the Southern Hemisphere). The North Star never appears to move at all, and it can be found due north. The Big Dipper and Cassiopeia will rotate around the North Star (also known as Polaris, since it is directly above the North Pole). When drawing the diagram, be sure to include the seven stars in the Big Dipper, the five in Cassiopeia, and the North Star. Make sure that the two stars at the end of the Big Dipper's "bowl" point to the North Star. Cassiopeia should be shaped like a somewhat flattened "W".
# Adventist Youth Honors Answer Book/Stars/Comet

A comet is a small body in the solar system that orbits the Sun and (at least occasionally) exhibits a coma (or atmosphere) and/or a tail — both due primarily to the effects of solar radiation upon the comet's nucleus, which itself is a minor planet composed of rock, dust, and ices.
Comets have highly elliptical orbits; they come very close to the sun (within the orbit of Mercury), and then they go way out to the edges of the solar system, far beyond even the orbit of Pluto. Because they travel over such a huge distance, it takes them many years to complete an orbit.
# Adventist Youth Honors Answer Book/Soil preparation

In general, you should follow the directions included with the plant you buy. Dig a hole to the proper depth as instructed. You will also want to control the soil's pH (acidity). Add lime to increase pH, or add manure to decrease it. Make sure these are well mixed with the soil though, because concentrated clumps can damage your plants. You can buy pH measuring kits and test the soil yourself. The soil should be well tilled and loose.
When you dig a hole to plant in, do not feel compelled to refill that hole with the same soil you removed from it. For the ambitious, there are dozens of soil recipes to choose from, combining loam, vermiculite, peat, lime, fertilizer, sand, compost, charcoal, manure, etc. You usually only need a gallon or so of soil per plant, not 40 acres of perfect dirt.
# Adventist Youth Honors Answer Book/Skill Level 3 Recreation

* Adventist Youth Honors Answer Book/Recreation/Rock Climbing - Advanced
* Adventist Youth Honors Answer Book/Recreation/Outdoor Leadership
* Adventist Youth Honors Answer Book/Recreation/Abseiling - Advanced
* Adventist Youth Honors Answer Book/Recreation/Wilderness Leadership - Advanced
* Adventist Youth Honors Answer Book/Recreation/Outdoor Leadership - Advanced
* Adventist Youth Honors Answer Book/Recreation/Scuba Diving
* Adventist Youth Honors Answer Book/Recreation/Scuba Diving - Advanced
* Adventist Youth Honors Answer Book/Recreation/Caving - Advanced
* Adventist Youth Honors Answer Book/Recreation/Community Water Safety - Advanced
* Adventist Youth Honors Answer Book/Recreation/Camp Safety - Advanced
# Adventist Youth Honors Answer Book/Stars/Constellation

A constellation is any one of the 88 areas into which the sky - or the celestial sphere - is divided. The term is also often used less formally to denote a group of stars visibly related to each other in a particular configuration or pattern.
Some well-known constellations contain striking and familiar patterns of bright stars. Examples are Ursa Major (containing the Big Dipper), and Orion (containing a figure of a hunter). Other constellations do not encompass any discernible star patterns, and contain only faint stars.
# Adventist Youth Honors Answer Book/Skill Level 3 Nature

* Adventist Youth Honors Answer Book/Nature/Stars - Advanced (North American Division)
* Adventist Youth Honors Answer Book/Nature/Reptiles - Advanced
* Adventist Youth Honors Answer Book/Nature/Trees - Advanced
* Adventist Youth Honors Answer Book/Nature/Cacti - Advanced
* Adventist Youth Honors Answer Book/Nature/Flowers - Advanced
* Adventist Youth Honors Answer Book/Nature/Amphibians - Advanced
* Adventist Youth Honors Answer Book/Nature/Grasses
* Adventist Youth Honors Answer Book/Nature/Stars - Advanced (General Conference)
* Adventist Youth Honors Answer Book/Nature/Marine Algae
* Adventist Youth Honors Answer Book/Nature/Maple Sugar - Advanced
* Adventist Youth Honors Answer Book/Nature/Rocks & Minerals - Advanced
* Adventist Youth Honors Answer Book/Nature/Lichens, Liverworts & Mosses
* Adventist Youth Honors Answer Book/Nature/Birds - Advanced
* Adventist Youth Honors Answer Book/Nature/Shells - Advanced
* Adventist Youth Honors Answer Book/Nature/Ecology - Advanced
# Adventist Youth Honors Answer Book/Skill Level 3 Outdoor Industries

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# Adventist Youth Honors Answer Book/Stalking and tracking

In order to come close to an animal, trackers must remain undetected not only by the animal, but also by other animals that may alert it. Moving as quietly as possible, trackers will avoid stepping on dry leaves and twigs, and take great care when moving through dry grass.
If the trackers are in close proximity to the animal, it is important that they remain downwind of it, that is, in a position where the wind is blowing away from the animal in the direction of the tracker. They must never be in a position where their scent could be carried in the wind towards the animal and thereby alert it. It is also important that the animal does not have the opportunity to cross their tracks, since the lingering human scent will alert it. Most animals prefer to keep the wind in their faces when traveling so that they can scent danger ahead of them. Trackers will therefore usually be downwind from them as they approach the animals from behind. The wind direction may, however, have changed. If the wind direction is unfavorable, the trackers may have to leave the spoor (tracks and other indications of an animal's presence) to search for their quarry from the downwind side.
As the trackers get closer to the animal, they must make sure that they see it before it sees them. Some trackers maintain that an animal keeps looking back down its own trail, always on the alert for danger coming from behind. When the spoor is very fresh, trackers may have to leave the spoor so that the animal does not see them first. Animals usually rest facing downwind, so that they can see danger approaching from the downwind side, while they can smell danger coming from behind them. An animal may also double back on its spoor and circle downwind before settling down to rest. A predator following its trail will move past the resting animal on the upwind side before realizing that the animal had doubled back, and the resting animal will smell the predator in time to make its escape.
When stalking an animal, trackers use the cover of bushes, going down on their hands and knees where necessary. In long grass they go down on their stomachs pulling themselves forward with their elbows. The most important thing is not to attract attention by sudden movements. Trackers should take their time, moving slowly when the animal is not looking, and keeping still when the animal is looking in their direction. When stalking an animal, trackers must also be careful not to disturb other animals. A disturbed animal will give its alarm signal, thereby alerting all animals in the vicinity, including the animal being tracked down.
Text from The Art of Tracking: The Origin of Science, by Louis Liebenberg, with permission from the author. Taken from Wikipedia:Tracking (hunting)
# Adventist Youth Honors Answer Book/Skill Level 3 Outreach

* Adventist Youth Honors Answer Book/Outreach/Parade Floats - Advanced
* Adventist Youth Honors Answer Book/Outreach/Preach It - Advanced
* Adventist Youth Honors Answer Book/Outreach/Crisis Intervention
* Adventist Youth Honors Answer Book/Outreach/Junior Youth Leadership