QCAA YEAR 11 PHYSICS UNIT 1

Describe the kinetic particle model

A model in which matter is made up of particles which are constantly moving.

What is thermal energy?

The internal energy present in a system due to its temperature; transfer of thermal energy when heating or cooling a substance. (Has the symbol of Q in the equation Q = mc∆T).

What is temperature?

The degree or intensity of heat present in a substance or object, expressed according to a comparative scale. (E.g The Celsius temperature scale).

What is kinetic energy?

The energy resulting from the movement of an object. When associated with the motion of particles in a substance.

What is heat?

The energy transferred from one system to another because in a difference in temperature.

What is internal energy?

The total potential energy and kinetic energy of the particles in a system.

What is conduction?

The process by which heat or electricity is directly transferred or transmitted through the material of a substance.

What is Convection?

Convection is the process in which a motion in gas or liquid in which the hotter/warmer portions rise and the colder portions sink.

Explain that a change in temperature is due to the addition and removal of energy from a system.

Temperature is the measure of heat. In order to increase the temp thermal (internal) energy needs to be added, which will increase the kinetic energy (heat from the movement of particles).

What is specific heat capacity?

The amount of thermal energy transfer needed to raise the temp by one kilogram of a substance by one degree.

Why does the temperature of a substance remain the same during the process of state change?

Because since the energy involved in a phase change is used to break bonds, there is no increase in kinetic energies of the particles, therefore no rise In temp.

What is Thermal equilibrium?

Is the state in which two objects

What is the Zeroth Law of dynamics?

The transfer of energy from a system with higher temperature to a system with lower temperature until thermal equilibrium is reached.

Explain the process in which thermal energy is transferred between two systems until thermal equilibrium is achieved and recognised this as the Zeroth law of thermodynamics.

As the transfer of thermal energy (through conduction, convection and radiation) continues the temperature difference between the two decreases. Eventually the systems will reach thermal equilibrium,where their temperatures are the same and there is no net transfer of thermal energy.

The Zeroth Law of dynamics further emphasises the concept of temperature and thermal equilibrium. It stated that if two systems are each in thermal equilibrium with a third system then they are in thermal equilibrium with each other.

What is Mechanical Work?

Mechanical work involves the application of force to move an object through a distance. It is a transfer of energy that can result in changes in a system's kinetic or potential energy.

Explain that a system with thermal energy has the capacity to do mechanical work.

A system with thermal energy can convert some of that thermal energy into mechanical work, or vice versa.

For example: A steam train. This happens by using a "working substance" such as water, from a higher temperature to a lower temperature.

Recall that the change in the internal energy of a system is equal to...

the energy added or removed by heating plus the work done on or by the system, and recognise this as the first law of thermo dynamics and that this is a consequence of the law of conservation of energy.

Explain that energy transfers and transformations in mechanical systems always result in some heat loss to the environment, so that the amount of usable energy is reduced.

For example: In the combustion engine of a car, not all of the heat energy in the exploding of the fuel, is converted into the kinetic energy of the wheels and car. There are unwanted losses from heat.

Define efficiency.

the ratio of the useful work performed by a machine or in a process to the total energy expended or heat taken in.

What is the Strong Nuclear Force?

It's the strongest force out of the 4 fundamental forces: 1. Strong Nuclear Force. 2. Electromagnetic Force. 3. The Weak Nuclear Force. 4. Gravitational Forces. It acts over small distances and keeps the nucleus together by overcoming the electromagnetic repulsion between protons.

Explain natural radioactive decay in terms of stability.

Stable:

Nuclear stability means that if a nucleus is stable it does not spontaneously emit any kind of radiation. This means it is non-radioactive.

Unstable:

If a nucleus is unstable it means it has the tendency to emit some kind of radiation. This makes it radioactive, and means it will decay.

What is Alpha radiation?

The composite particle consisting of 2 protons and 2 neutrons tightly bonded together emitted from the nucleus of some radionuclides.

What is Beta Minus Decay?

A type of radioactive decay in which an energetic electron and associated auntineutrino are emitted from an atomic nucleus.

What is Beta Plus Decay?

A type of radioactive Decay in which an energetic positron and associated neutrino are emitted from an atomic nucleus.

What is Gamma Radiation?

Extremely high frequency electromagnetic radiation (high frequency photons) emitted from the nucleus of some radionuclide.

Describe Alpha radiation

• Lowest penetrating abilities, can be stopped by a sheet of paper.

• Carry a positive charge.

• Relatively massive.

• Consists of 2 protons and 2 neutrons.

• Have high ionisation ability due to their positive charge and large mass.

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Describe Beta Radiation.

• Moderate penetrating abilities.

• Can be either positive or negatively charged.

• Beta plus have a charge of +e (charge of positron) while Beta Minus have a charge of -e (charge of an electron).

• Moderate ionisation ability.

Describe Gamma Radiation.

• Highest penetrating ability.

• No charge.

• No mass.

• Low ionisation ability.

Explain how an excessive of protons neutrons or a mass in a nucleus can result in Alpha, Beta positive and Beta negative decay.

If a nucleus is unstable it will emit some kind of radiation. This will make it radioactive because it will decay in an attempt to become stable.

A nucleus with an excessive number of protons or neutrons will undergo Beta decay. Heavier elements will undergo Alpha decay.

Define half-life.

The time taken for half of the atoms in a sample of the material to undergo radioactive decay.

Describe energy in terms of electron volts (eV) and joules (J)

Energy is measured in joules but can be measured in the units of electron volts (eV).

An electron volt is the work done on an electron to accelerate it through a potential difference of 1 volt.

What is the definition of artificial transmutation?

Artificial transmutation is the process of changing one element into another by bombarding it with high-energy particles.

What is the key difference between artificial transmutations and natural radioactive decay?

Artificial transmutations involve deliberately changing an element's nucleus, while natural radioactive decay is a spontaneous process.

What is nuclear fission?

Nuclear fission is the process of splitting an atomic nucleus into smaller nuclei, accompanied by the release of a significant amount of energy.

Explain a neutron-induced fission reaction.

In a neutron-induced nuclear fission reaction, a neutron collides with a heavy nucleus, causing it to split into two smaller nuclei, releasing additional neutrons and a large amount of energy.

What is a fission chain reaction?

A fission chain reaction is a self-sustaining process in which the neutrons produced during nuclear fission cause additional fission reactions, leading to a continuous release of energy.

What is nuclear fusion?

Nuclear fusion is the process of combining two light atomic nuclei to form a heavier nucleus, accompanied by the release of energy.

What is mass defect?

Mass defect is the difference between the mass of an atomic nucleus and the sum of the masses of its individual protons and neutrons.

What is binding energy?

Binding energy is the energy required to hold the protons and neutrons together within the nucleus of an atom.

What is binding energy per nucleon?

Measures the average amount of energy that holds each nucleon (proton or neutron) in the nucleus, providing insight into nuclear stability.

What is Einstein's mass-energy equivalence relationship?

Einstein's mass-energy equivalence relationship, expressed as E=mc², states that energy (E) is equivalent to mass (m) times the speed of light (c) squared.

Why does nuclear fusion release more energy per nucleon than nuclear fission?

Nuclear fusion releases more energy per nucleon because a greater percentage of the mass is transformed into energy during fusion reactions.

What carries electric current in a circuit?

Electrons

What is the Law of Conservation of Electric Charge?

The total electric charge of an isolation system remains constant regardless of changes within the system.

What is Kirchhoff's Current law?

At any node in an electrical circuit, electric charge is conserved such that the sum of the electric currents flowing into a node is equal to the sum of electric current flowing out of that node.

What is electric current?

Electric current is the rate of flow of electric charge in a circuit, typically measured in amps.

What is Electrical potential difference?

Is the energy per unit charge required to move electric charges between two points in a circuit, measured in volts (V).

What is the definition of power?

The rate at which work is done for the rate at which energy is transferred or transformed.

What is Kirchhoff's Voltage Law?

The energy inputs in a circuit is equal to the sum of energy outputs from the loads in the circuit such that the directed sum of the electrical potential differences around any closed network is zero.

Recall that the energy available to electric charges moving in an electrical circuit is measured using...

electrical potential difference

What is resistance?

The ratio between the voltage applied to the current flowing through a circuit.

What is Ohm's Law and Ohm's equation?

That electric current is proportional to voltage and inversely proportional to resistance.

V = IR

What are the differences between Ohmic and non-Ohmic resistors?

Ohmic Resistors:

Constant Resistance: Regardless of the applied voltage, Ohmic resistors maintain a constant resistance value.

Linear Relationship: The voltage-current graph for Ohmic resistors is a straight line passing through the origin (0,0), indicating a linear relationship between voltage and current.

Non-Ohmic Resistors:

Non-Linear Behavior

Variable Resistance: The resistance of non-Ohmic resistors varies with voltage, current, temperature, or other external factors.

What is power dissipation?

A measure of the rate at which energy is lost from an electrical system; power dissipation of a resistor can be calculated using the formula P= VI

In the core of a Nuclear Power Plant there us water that is used as a moderator, as well as cadmium control rods. Explain the function of both the moderator and control rods, in terms of the free neutrons initiate fission reactions

In the core of a Nuclear Power Plant there is water that us used as a moderator, it is used to slow down the neutrons by cooling them or removing their kinetic energy. The control rods are made up of Cadmium and it slides between the nuclear material and intercepts the free neutrons, which prevents them from causing nuclear reactions.

What are the formulas in Unit 1?

Tk = Tc + 273

Q = mcdeltaT

∆𝑈 = 𝑄 + 𝑊

𝜂 = energy output energy input × 100/1 %

𝑁 = 𝑁𝑜( 1 /2 )^n

Balancing Equations

𝐼 = 𝑞/𝑡

𝑉 = 𝑊/𝑞

𝑃 = 𝑊 /t

V = IR

𝑃 = 𝑉i

𝑃 = 𝐼^2𝑅

𝑉𝑡 = 𝑉1 + 𝑉2 + ⋯

Explain a Fission and Fusion reaction graph in terms of the energy released in fission and fusion reactions, and the binding energy per nucleon involved.

On the graph it is clear that the peak binding energy per nucleon occurs in the region of stability around Iron(Fe) (If it's not iron put a different element) it is also clear that the yield from fusion is much greater per nucleon than fission. The products from a fusion reaction have much more binding energy per nucleon compared to the reactants.

What are the advantages and disadvantages of coal powered electricity?

Advantages:

Coal can be found anywhere.

Inexpensive to build and can be quickly ramped up or down to meet changes in demand.

Disadvantages:

Releases large amounts of CO2

Environmental impacts such as soil and water contamination.

Requires large amount of water for cooling, which limits water resources.