OpenLLM-France/wikimedia huggingface dataset:
# A-level Physics (Advancing Physics)/Electron Behaviour as a Quantum Phenomenon/Worked Solutions

1. An electron moves at 30,000 ms$^{−1}$. What is its de Broglie wavelength?
$\lambda ={\frac {h}{mv}}={\frac {6.626\times 10^{-34}}{9.1\times 10^{-31}\times 30{,}000}}=2.43\times 10^{-8}\,\mathrm {m}$
2. What is its frequency?
$f={\frac {E_{\mathrm {kinetic} }}{h}}={\frac {{\tfrac {1}{2}}\,9.1\times 10^{-31}\times 30{,}000^{2}}{6.626\times 10^{-34}}}=6.18\times 10^{11}\,\mathrm {Hz}$
3. What is its kinetic energy, in eV?
From the top half of the fraction in the previous question:
$E_{\mathrm {kinetic} }={\tfrac {1}{2}}\,9.1\times 10^{-31}\times 30{,}000^{2}=4.10\times 10^{-22}\,\mathrm {J} ={\frac {4.10\times 10^{-22}}{1.6\times 10^{-19}}}\,\mathrm {eV} =2.56\,\mathrm {meV}$
4. Given that it is travelling out of an electron gun, what was the potential difference between the anode and the cathode?
2.56 mV – that's why we use eV!
5. An electron is accelerated by a potential difference of 150 V. What is its frequency?
$E_{\mathrm {kinetic} }=1.6\times 10^{-19}\times 150=2.4\times 10^{-17}\,\mathrm {J}$
$f={\frac {E_{\mathrm {kinetic} }}{h}}={\frac {2.4\times 10^{-17}}{6.626\times 10^{-34}}}\,\mathrm {Hz} =3.62\times 10^{16}\,\mathrm {Hz}$
# A-level Physics (Advancing Physics)/Energy Levels/Worked Solutions

The following table gives the wavelengths of light given off when electrons change between the energy levels in hydrogen as described in the first row:
| Transition of n | 3→2 | 4→2 | 5→2 | 6→2 | 7→2 | 8→2 | 9→2 | ∞→2 |
| Wavelength (nm) | 656.3 | 486.1 | 434.1 | 410.2 | 397.0 | 388.9 | 383.5 | 364.6 |
| Colour | Red | Blue-green | Violet | Violet | (Ultraviolet) | (Ultraviolet) | (Ultraviolet) | (Ultraviolet) |
1. Calculate the potential energy of an electron at level n=2.
$c=\lambda f$
$3\times 10^{8}=364.6\times 10^{-9}\times f$
$f=8.23\times 10^{14}{\mbox{ Hz}}$
$\Delta E=-hf=-6.63\times 10^{-34}\times 8.23\times 10^{14}=-5.46\times 10^{-19}{\mbox{ J}}=-3.41{\mbox{ eV}}$
2. Calculate the difference in potential energy between levels n=2 and n=3.
This time, let's derive a general formula:
$f={\frac {\Delta E}{h}}$
$c={\frac {\lambda \Delta E}{h}}$
$\Delta E={\frac {ch}{\lambda }}={\frac {3\times 10^{8}\times 6.63\times 10^{-34}}{656.3\times 10^{-9}}}=3.03\times 10^{-19}{\mbox{ J}}=1.89{\mbox{ eV}}$
3. What is the potential energy of an electron at level n=3?
$-3.41+1.89=-1.52{\mbox{ eV}}$
4. If an electron were to jump from n=7 to n=5, what would the wavelength of the photon given off be?
$\Delta E={\frac {ch}{\lambda _{5,2}}}-{\frac {ch}{\lambda _{7,2}}}=ch\left({\frac {1}{\lambda _{5,2}}}-{\frac {1}{\lambda _{7,2}}}\right)=3\times 10^{8}\times 6.63\times 10^{-34}\left({\frac {1}{434.1\times 10^{-9}}}-{\frac {1}{397\times 10^{-9}}}\right)=-4.28\times 10^{-20}{\mbox{ J}}$
$\lambda ={\frac {-ch}{\Delta E}}={\frac {3\times 10^{8}\times 6.63\times 10^{-34}}{4.28\times 10^{-20}}}=4.65{\mbox{ }}\mu {\mbox{m}}$
5. Prove that the wavelength of light emitted from the transition n=4 to n=2 is 486.1 nm (HINT: $e=hf$ and $c=f\lambda$)
$13.6({\frac {1}{2^{2}}}-{\frac {1}{4^{2}}})=2.55eV$
$2.55eV={\frac {hc}{\lambda }}$ therefore $\lambda ={\frac {hc}{2.55\times 1.6\times 10^{-}19}}=4.875\times 10^{-}7=488nm$
# A-level Physics (Advancing Physics)/Energy in Simple Harmonic Motion/Worked Solutions

1. A 10g mass causes a spring to extend 5 cm. How much energy is stored by the spring?
Gravitational Potential Energy transferred completely to Elastic Potential Energy
Gravitational Potential Energy = mass x gravity x height
GPE $=0.01m\times 0.05kg\times 9.8Nkg^{-1}=4.9\times 10^{-3}J$
2. A 500g mass on a spring (k=100) is extended by 0.2m, and begins to oscillate in an otherwise empty universe. What is the maximum velocity which it reaches?
${\frac {1}{2}}mv_{max}^{2}={\frac {1}{2}}kx_{max}^{2}$
$v_{max}^{2}={\frac {kx_{max}^{2}}{m}}$
$v_{max}=x_{max}{\sqrt {\frac {k}{m}}}=0.2\times {\sqrt {\frac {100}{0.5}}}=2.83{\mbox{ ms}}^{-1}$
3. Another 500g mass on another spring in another otherwise empty universe is extended by 0.5m, and begins to oscillate. If it reaches a maximum velocity of 15ms$^{−1}$, what is the spring constant of the spring?
${\frac {1}{2}}mv_{max}^{2}={\frac {1}{2}}kx_{max}^{2}$
$k={\frac {mv_{max}^{2}}{x_{max}^{2}}}={\frac {0.5\times 15^{2}}{0.5^{2}}}=450{\mbox{ Nm}}^{-1}$
4. Draw graphs of the kinetic and elastic energies of a mass on a spring (ignoring gravity).
$E_{e}\propto \cos ^{2}\omega t$
$E_{k}\propto \sin ^{2}\omega t$
5. Use the trigonometric formulae for x and v to derive an equation for the total energy stored by an oscillating mass on a spring, ignoring gravity and air resistance, which is constant with respect to time.
$x=A\cos {\omega t}$
$v=-A\omega \sin {\omega t}$
Substitute these into the equation for the total energy:
$\Sigma E={\frac {1}{2}}(kx^{2}+mv^{2})={\frac {1}{2}}(k(A\cos {\omega t})^{2}+m(-A\omega \sin {\omega t})^{2})={\frac {1}{2}}(kA^{2}\cos ^{2}{\omega t}+mA^{2}\omega ^{2}\sin ^{2}{\omega t})={\frac {A^{2}}{2}}(k\cos ^{2}{\omega t}+m\omega ^{2}\sin ^{2}{\omega t})$
We know that:
$\omega ={\sqrt {\frac {k}{m}}}$
Therefore:
$\omega ^{2}={\frac {k}{m}}$
By substitution:
$\Sigma E={\frac {A^{2}}{2}}(k\cos ^{2}{\omega t}+{\frac {mk}{m}}\sin ^{2}{\omega t})={\frac {A^{2}}{2}}(k\cos ^{2}{\omega t}+k\sin ^{2}{\omega t})={\frac {kA^{2}}{2}}(\cos ^{2}{\omega t}+\sin ^{2}{\omega t})={\frac {kA^{2}}{2}}$
# A-level Physics (Advancing Physics)/Finding the Distance of a Remote Object

In the final section (Section C) of the exam, you have to be able to write about how waves are used to find the distance of a remote object. I would recommend that you pick a method, and then answer the following questions about it:
1. What sort of wave does your system use? What is an approximate wavelength of this wave?
2. What sort of distance is it usually used to measure? What sort of length would you expect the distance to be?
3. Why is measuring this distance useful to society?
4. Draw a labelled diagram of your system.
5. Explain how the system works, and what data is collected.
6. Explain how the distance to the object is calculated using the data collected.
7. What limitations does your system have? (e.g. accuracy, consistency)
8. What percentage error would you expect these limitations to cause?
9. How might these problems be solved?

## Examples

Some example answers to these questions are given in the following pages:
* Radar
* Sonar
# A-level Physics (Advancing Physics)/Electron Behaviour as a Quantum Phenomenon

So far, we have considered how quantum physics applies to photons, the quanta of light. In reality, every other particle is also a quantum, but you only need to know about photons and electrons.
The image on the right shows what happens when you fire electrons through a pair of slits: it arrives in lumps, but you get fringes due to superposition as well. The electrons are behaving as both waves and particles. Actually, they are behaving as quanta. The equations describing quantum behaviour in electrons are similar to those describing it in photons.

## Frequency and Kinetic Energy

We know that, for photons:
$f={\frac {E}{h}}$
In suggesting that electrons are quanta, we assume that they must have a frequency at which the phasors representing them rotate. We also know that h is a constant; it does not change. So, when adapting the above equation to apply to electrons, all we need to adapt is E. In electrons, this energy is their kinetic energy. If the electron has some form of potential energy, this must first be subtracted from the kinetic energy, as this portion of the energy does not affect frequency. So:
$f={\frac {E_{kinetic}-E_{potential}}{h}}$

## De Broglie Wavelength

If electrons exhibit some wavelike properties, they must also have a 'wavelength', known as the de Broglie wavelength, after its discoverer. This is necessary in order to work out a probability distribution for the position of an electron, as this is the distance the electron travels for each phasor arrow rotation. The de Broglie wavelength λ is given by the equation:
$\lambda ={\frac {h}{p}}={\frac {h}{mv}}$,
where h = Planck's constant, p = momentum, m = mass of electron = 9.1 x 10$^{−31}$kg and v = velocity of electron.

## Potential Difference and Kinetic Energy

Potential difference is what causes electrons to move. You already know how power is related to charge, voltage and time:
$P={\frac {QV}{t}}$
Since power is the rate at which work is done:
$W=QV\,$
We know that the charge on an electron equals -1.6 x 10$^{−19}$, and that work done is energy, so:
$E_{kinetic}=1.6\times 10^{-19}\times V$
Energy, in the SI system of units, is measured in Joules, but, sometimes it is measured in electronvolts, or eV. 1 eV is the kinetic energy of 1 electron accelerated by 1V of potential difference. So, 1 eV = 1.6 x 10$^{−19}$ J.

## Questions

1. An electron moves at 30,000 ms$^{−1}$. What is its de Broglie wavelength?
2. What is its frequency?
3. What is its kinetic energy, in eV?
4. Given that it is travelling out of an electron gun, what was the potential difference between the anode and the cathode?
5. An electron is accelerated by a potential difference of 150V. What is its frequency?
Worked Solutions
# A-level Physics (Advancing Physics)/Electron Behaviour as a Quantum Phenomenon/Momentum

All moving objects have momentum. Momentum is the product of the velocity of an object and its mass, so:
$p=mv\,$
Momentum is usually denoted p, and is measured in kgms$^{−1}$. Momentum is used when considering collisions of bodies as momentum, in a closed system, is constant. Force is the rate of change of momentum, so:
$F={\frac {\Delta p}{t}}$
# Adventist Youth Honors Answer Book/Recreation/Rock Climbing - Advanced

Rock Climbing - Advanced :
| Recreation General Conference | Skill Level 3 |
| Recreation General Conference | Year of Introduction: 1970 |
Rappel Master Certified Instructor Required.

## 1. Have the Rock Climbing Honor.

Instructions and tips for earning the Rock Climbing honor can be found in the Recreation chapter.
# Adventist Youth Honors Answer Book/Recreation/Scuba Diving

Scuba Diving :
| Recreation General Conference See also Scuba Diving - Advanced | Skill Level 3 |
| Recreation General Conference See also Scuba Diving - Advanced | Year of Introduction: 1967 |
# Adventist Youth Honors Answer Book/Recreation/Scuba Diving - Advanced

Scuba Diving - Advanced :
| Recreation General Conference | Skill Level 3 |
| Recreation General Conference | Year of Introduction: 1967 |

## 1. Have the Scuba Diving Honor.

Instructions and tips for earning the Scuba Diving honor can be found in the Recreation chapter.
# Automotive Systems/Engine Electrical

Electrical systems are becoming more and more important in automobiles. An electrical circuit can be found in every part of a modern car, from heated seats, to power windows, to computer controlled engine components. A modern car even has electrical circuits in the tires. In 2008, vehicles in the USA were required to have tire pressure monitors that would alert the driver if tire pressure was more than twenty percent off of the recommended pressure. Electrical systems will only get more important in the future with the increasing sales of hybrids and fully electric cars. The majority of automobiles today have what is referred to as a 12 volt system, although in reality a healthy battery will have about 12.65 volts. When the engine is running, the alternator will increase this charge to around 14 volts. Some hybrid cars can generate as much as 400 volts.(1) The engine electrical system includes circuits and components such as the battery, alternator, and devices used for ignition and engine control. Engine electrical wires fall under two categories, primary and secondary. Primary systems are the low power systems, 16 volts or less, and secondary wiring carries the higher amperages to be found under the hood. These high amp wires include the spark plug wires and the wire that goes from the distributor cap to the starter coil. The other wires that attach to the starter coil are low voltage primary wires. The higher voltage is created inside the coil. The positive wire that attaches to the starter is also a secondary wire. Starters draw heavy amperage loads. The starter circuit is the only circuit in a car that is not fused. Secondary wires that contain higher voltages should not be tested with a meter that is not designed for the load. They can be recognized by their large diameter.
(1)(Halderman, James D. Automotive Technology, Principles, Diagnosis, and Service p 353.)
# Automobile Repair/Volvo

See the Volvo Cars Wikipedia page for full model information. For repair information, use the Volvo model links below.

## Passenger Vehicle Models

* PV444 : 1943–1958
* PV544 : 1958–1966
* P1800 : 1961–1973
* 120 : 1956–1970
* 140 : 1966–1974
* 164 : 1968–1975
* 240 : 1974-1993
* 260 : 1976-1982
* 740 : 1984–1992
* 760 : 1982–1990
* 780 : 1986–1990
* 850 : 1992–1997
* 940 : 1990-1998
* 960 : 1990–1998
* C30 : 2007–2013
* C70 : 1996–2013
* S40 : 1995–2019
* S60 : 2001–Present
* S70 : 1997–2000
* S80 : 1999–2016
* S90 : 1996-1998, 2017–Present
* V40 : 1995–2004
* V50 : 2004–2012
* V60 : 2010-Present
* V70 : 1996-2016
* V90 : 1996-1998, 2016–Present
* XC70 : 1998-2016
* XC90 : 2002–Present
# Automotive Systems/Cooling System

Cooling systems remove heat from the engine using the properties of heat transfer. Modern cars use liquid cooling systems. These use a fluid circulated within the engine, that is then pumped out of the engine into a radiator, where the heat is released. Less common is the air cooled engine. These engines are common in non automotive applications, and have been used successfully in cars. Air cooled engines use airflow over the surface of the engine to remove excess heat. Automotive applications generally include a fan to force air over the engine.
In a liquid cooled engine, the liquid coolant is a mixture of distilled water and antifreeze, of which the base ingredient is methyl alcohol. The fluid is pumped through channels that are manufactured into the engine block. The fluid draws heat out of the engine and flows into the radiator to be cooled. The radiator is a set of pipes with thousands of thin metal fins mounted them. The fins conduct the heat out of the liquid which is cooled enough to be cycled back into the engine to repeat the process. The radiator has a fan that blows outside air against the fins. This increases the amount of air that flows over the cooling fins of the radiator and allow for more heat to be removed from the liquid coolant.
Since combustion engines operate better at a higher temperature, a device called a 'thermostat' is designed into the cooling system of modern engines to help them warm up more quickly. A thermostat is a small valve in the cooling system which is closed when the engine is cold. This blocks the coolant from flowing into the radiator and allows it to heat up at a quicker pace. As the coolant reaches the desired temperature, wax in the thermostat melts and pressurizes which forces the valve open. The coolant is now able to flow into the radiator ensuring that the engine temperature stays constant and does not overheat.
# Automobile Repair/Volvo/240
## Section 1 : Maintenance
### Maintenance Schedule

Every 10k miles or 1 year
Engine
* Replace oil, oil filter, air filter
* Check coolant level, inspect for leaks
* Check ignition system, spark plug wires, distributor cap
* Inspect exhaust system for damage, corrosion
* Inspect accessory belts for wear
Transmission
* Check clutch and drive shaft for play
* Check transmission fluid level and add if needed
* Check for leaks at the transmission, axle and cooling lines
Electrical
* Check battery voltage and inspect terminal connections
* Check operation of all exterior lights
Chassis
* Check brake and emergency brake operation
* Check brake pad wear
* Inspect brake system for leaks
* Fill brake fluid reservoir if needed
* Inspect steering and suspension parts for play or wear
* Check tires for wear and correct pressure
Every 20k miles or 2 years
Repeat all 10k maintenance as well as:
Chassis
* Replace brake fluid
Every 30k miles or 3 years
Repeat all 10k maintenance as well as:
Engine
* Replace coolant
* Replace spark plugs
Transmission
* Replace ATF
Every 40k miles or 4 years
Repeat all 10k and 20k maintenance
Every 50k miles or 5 years
Repeat all 10k maintenance as well as:
Engine
* Replace engine timing belt

## Section 2 : Engines
### General

Gasoline
* B17 : I4 - 1784 cc
* B19 : I4 - 1986 cc
* B200 : I4 - 1986 cc
* B20 : I4 - 1986 cc
* B21 : I4 - 2127 cc
* B23 : I4 - 2316 cc
* B230 : I4 - 2316 cc
* B27 : V6 - 2664 cc
* B28 : V6 - 2849 cc
* B280 : V6 - 2849 cc
Diesel
* D20 : I5 - 1986 cc
* D24 : I6 - 2383 cc

### Fuel Delivery

Volvo 240s were offered with 3 core types of fuel delivery systems.

#### Carburetor

SU Carburetor: The earliest 240 models had SU Carburetors.

#### Mechanical Fuel Injection

Bosch K-Jetronic

#### Electronic Fuel Injection

* Bosch LH-Jetronic 1.0
* Bosch LH-Jetronic 2.0
* Bosch LH-Jetronic 2.2
* Bosch LH-Jetronic 2.4
* Bosch LH-Jetronic 3.1

## Section 4 : Transmissions
### General

Manual
* M45 : 4-speed
* M46 : 4-speed
* M47 : 5-speed
Automatic
* BW35 : 3-speed
* BW55 : 3-speed
* AW55 : 3-speed
* AW70 : 4-speed
* AW71 : 4-speed
# Automotive Systems/Differential

The differential is a device that splits power between 2 wheels. As a car drives straight, its wheels will travel the same distance and rotate at the same speed. When a car turns, the outside wheels will follow a longer path around the curve. If the inside and outside wheels were connected by a mechanically solid axle, they would force each other to rotate at the same speed. The speed difference between the wheels on the shorter, inside path and the wheels on the longer, outside path would result in tire wear, poor handling, and if the traction of the tires were too great, the axle itself could be damaged.
Automobiles can have several types of differentials; Open, Limited-Slip, and Locking. An open differential lets either wheel spin at any speed traction allows. The majority of cars on the road have this kind of differential. A limited slip differential has either viscous liquid or small clutch packs to allow power to go to the wheel with traction while the other wheel is spinning without traction. This type of differential is mostly seen on sports cars. A locking differential uses a mechanical connection to lock or unlock both wheels. The only usual application for this is off-roading in trucks or SUVs.
# Automotive Systems/Electrical System

The Chassis electrical system is comprised of all wiring and components except for those used by the engine, its ancillaries, and any engine control circuits. The chassis electrical system includes items such as headlights and driver accessories. The chassis electrical system does share the alternator, battery and certain other items such as the ignition switch and to a certain degree the instrument cluster.
The most widely used battery is the lead-acid type. However, the following types shall also used;
* Alkaline Battery
* Zinc-air Battery
* Nickel-Metal hydride Battery
* Lithium-ion Battery
LEAD-ACID BATTERY
It consist of;
. container . plates . separators . electrolyte
# Adventist Youth Honors Answer Book/Quilt/Make a quilt

A good way to meet this requirement is to make a quilt as a club. Send each Pathfinder home with a square of cloth and instruct them to decorate and sign it. The squares can be decorated with appliques, fabric paint, tie-dye, or any other method that will survive the laundry. When everyone brings their squares in, proceed as described in the previous requirement.
# Adventist Youth Honors Answer Book/Recipes/Corn bread

Corn Bread :
| Ingredients | Procedure |
| 1 cup warm water 1 tablespoon yeast 4 tablespoons sugar 1 cup yellow cornmeal ½ cup white flour ½ cup whole wheat flour 1 teaspoon salt | Mix water yeast and sugar. Let this sit for a few minutes until it bubbles. Stir in the rest of the ingredients, adding water until it is pourable. Bake in a greased 9x9 pan at 350°F (175°C) for 25 minutes or until the edges turn golden brown. Serves 16 |
# Adventist Youth Honors Answer Book/Quilt/Tying

Quilting is a sewing method done either by hand, by sewing machine, or by a longarm quilting system. The process uses a needle and thread to join two or more layers of material together to make a quilt. Typical quilting is done with three layers, the top fabric or quilt top, batting or insulating material and backing material. The quilter's hand or sewing machine passes the needle and thread through all layers and then brings the needle back up. The process is repeated across the entire piece where quilting is wanted. A straight or running stitch is commonly used and these stitches can be purely functional or decorative and elaborate.
Another technique for securing the quilt layers is tying. Tying refers to the technique of using thread, yarn or ribbon to pass through all three layers of the quilt at regular intervals. These "ties" hold the layers together during use and especially when the quilt is washed. This method is easier and more forgiving if the quilt is made by hand. Tied quilts are called, depending on the regional area, "lap", "comfort" or "comforter", among other names.
# Adventist Youth Honors Answer Book/Recipes/Butternut Squash

Butternut Squash :
| Ingredients | Procedure |
| 1 Butternut Squash 4 tablespoons Maple Syrup 4 tablespoons Butter Cooking Spray | Spray the inside of a Dutch Oven and the underside of the lid with cooking spray. Slice the butternut squash in half lengthwise. Using a spoon, scoop out the seeds and discard them. Place the squash halves in the dutch oven, cut side up. You may have to place the large end of one half next to the small end of the other to make them fit. Slice the butter in to pats and place them on the squash halves. Put the lid on and bake for 45 minutes at 350°F. Remove the squashes from the dutch oven and drizzle maple syrup on them. Serves 2-4 |
# Adventist Youth Honors Answer Book/Quilt/Types
## Block Quilts

Block quilts are made by piecing rectangular (usually square) blocks of cloth together. This forms a regular pattern. The blocks may be decorated with fabric paint, appliqués, or other methods. They can be made from cloth with a single solid color or from prints.

## Crazy Quilts

This art form was developed in United States during the 1880's when it created quite a stir. Crazy quilting does not actually refer to a specific kind of quilting (the needlework which binds two or more layers of fabric together), but a specific kind of patchwork. Crazy quilts rarely have the internal layer of batting that is part of what defines quilting as a textile technique.
Regular patchwork combines the pieces of fabric into a predetermined and regular design, but crazy patchwork uses irregular pieces of fabric on a foundation fabric or paper. This may create haphazard-looking and asymmetrical designs, or the designer may use some control in placement. The patches and seams are then usually heavily embellished.

## Medallion Quilts

A medallion quilt starts with a center motif and is then surrounded by multiple boarders. The center is often a large square or star.

## Pictorial Quilts

Pictorial Quilts are planned much like a painting. The artist would plan the colors and patterns of each part or item represented in the "picture" before beginning. Each piece would be cut carefully and then be stitched onto the quilt top to form the picture. Great care must be taken in piecing items in order (for example: for a nature scene, items in the foreground of the picture should be stitched on last.