Physics Year 2

Front 1

Free Vibrations

Back 1

Free vibration is where a system is given an initial displacement and then allowed to vibrate/oscillate freely.

Front 2

Forced Vibration

Back 2

Forced vibration is where a driving force is continuously applied to make the system vibrate/oscillate.

Front 3

Driving frequency

Back 3

The thing that provides the driving force will be moving at a certain frequency.

Front 4

natural frequency, f0

Back 4

The system will oscillate at a set frequency freely

Front 5

What Damping Forces do

Back 5

-oppose the motion of the oscillating body, they slow or stop simple harmonic motion from occurring. ​

- act in the opposite direction to the velocity.

Front 6

Light Damping

Back 6

slowly reduces the amplitude of the oscillations, but keeps the time period almost constant.

Front 7

Heavy Damping

Back 7

allows the body to oscillate but brings it quickly to rest.

Front 8

Critical Damping

Back 8

brings the body back to the equilibrium point very quickly with out oscillation.

Front 9

Over Damping

Back 9

also prevent oscillation but makes the body take a longer time to reach equilibrium.

Front 10

Damping affects on Resonance

Back 10

Damping reduces the size of the oscillations at resonance.

Front 11

Radial Field

Back 11

The field lines end at the centre of a mass and tail back to infinity. We can see that they become more spread out the further from the mass we go.

Front 12

Uniform Fields

Back 12

The field lines are parallel in a uniform field.

Front 13

Why is Gravitational Potential Negative?

Back 13

The gravitational field is attractive so work is done by the field in moving the mass, meaning energy is given out.

Front 14

Current when Discharging a Capacitor

Back 14

There is initially a large current as the electrons leave the negative plate. As the number of electrons on the negative plate falls so does the size of the repulsive electrostatic force, this makes the current fall at a slower rate. When no more electrons move in the circuit the current drops to zero.

Front 15

Magnetic Field Lines

-Direction they act North and south

Back 15

Magnetic field lines leave the North Pole of the magnet and enter the South Pole..

Front 16

Lenz’S Law

Back 16

The direction of the e.m.f. induced in a conductor is such that it opposes the change producing it.

Front 17

Nuclear Model how it came about

Back 17

Rutherford used these results to make the following conclusions:

Most of the mass must be gathered in one small volume – the nucleus.

​They can repel a fast moving alpha particle

The nucleus must be positively charged.

​They repel positive alpha particles

Most of the atom is empty space.

​Only 1 in 8000 alpha particles are deflected

Negative electrons orbit the nucleus at a large distance from it.

​Negative charges are needed to keep the atom neutral

Hint 17

Observations and Conclusions

Front 18

Decay Constant

Back 18

Every radioactive isotope has its own probability that a nucleus will decay

Front 19

Activity

Back 19

The activity of a radioactive source is the number of decays that happen every second.

Front 20

Half Life

Back 20

The time it takes for the number of atoms in a sample to drop to half of its original sample

or

The time it takes for the activity of a substance to drop to half of its original activity

Front 21

N against Z Graph

Back 21

Back (Definition)

Follows N=Z around Z=20, then curves to go through Z=80 N=120

β- emitters above the line, β+ emitters below the line and α at the top

Front 22

Electron Diffraction Equation

Back 22

Back (Definition)

Front 23

Mass deflect

Back 23

Disappearing Mass

The mass of a nucleus is less than the mass of the protons and neutrons that it is made of.

(mass of protons + mass of neutrons) – mass of nucleus = ∆m

∆m is the difference in the masses and is called the mass defect.

Front 24

Binding Energy

Back 24

As the protons and neutrons come together the strong nuclear force pulls them closer and they lose potential energy.

Energy must be done against the s.n.f. to separate the nucleus into the nucleons it is made of.

Front 25

Critical Mass

Back 25

For a chain reaction to happen the mass of the fissionable material must be greater than a certain minimum value.

Front 26

Fuel Rod

Back 26

This is where nuclear fission reactions happen. They are made or Uranium and there are hundreds of them spread out in a grid like pattern.

Front 27

Enriched Uranium

Back 27

The Uranium that is used in fuel rods has a higher percentage of 235

Front 28

Moderator

Back 28

The neutrons that are given out from nuclear fission are travelling too fast to cause another fission process.

Front 29

Thermal Neutrons

Back 29

Neutrons that are travelling slow enough to cause a fission process

Front 30

Coolant

Back 30

Heat is carried from the moderator to the heat exchanger by the coolant. The pressuriser and the pump move the hot coolant to the heat exchanger, here hot coolant touches pipes carrying cold water. Heat flows from hot coolant to cold water turning the water into steam and cooling the coolant. The steam then leaves the reactor (and will turn a turbine) as the coolant return to the reactor.

Front 31

Control rods

Back 31

For the reactor to transfer energy at a constant rate each nuclear fission reaction must lead to one more fission reaction. Since each reaction gives out two or more we must remove some of the extra neutrons. The control rods absorb neutrons, reducing the amount of nuclear fission processes occurring and making the power output constant. They can be lowered further into the fuel rods to absorb more neutrons and further reduce the amount of fission occurring. Some neutrons leave the reactor without interacting, some travel too fast while other are absorbed by U238 nuclei. If we need more neutrons we can raise the control rods.

Front 32

Control rods

Back 32

For the reactor to transfer energy at a constant rate each nuclear fission reaction must lead to one more fission reaction. Since each reaction gives out two or more we must remove some of the extra neutrons. The control rods absorb neutrons, reducing the amount of nuclear fission processes occurring and making the power output constant. They can be lowered further into the fuel rods to absorb more neutrons and further reduce the amount of fission occurring. Some neutrons leave the reactor without interacting, some travel too fast while other are absorbed by U238 nuclei. If we need more neutrons we can raise the control rods.

Front 33

Nuclear Reactor Safety

Back 33

-Fuel Used

Using solids rather than liquids avoids the danger of leaks or spillages. They are inserted and removed from the reactor by remote controlled handling devices.

-Shielding

- Emergency Shutdown

Front 34

Disposal of high level radioactive waste

Back 34

How do we get rid? The spent fuel rods are taken from the reactor and stored in cooling ponds with in the power station to allow most of the short-term radioactivity to die away. It is then transported to a processing plant. Here it is encased in steel containers and kept under water.

The cladding is eventually removed and the fuel rods are separated into unused uranium and plutonium and highly radioactive waste.

The uranium and plutonium is kept in sealed container for possible future use.

The waste is converted into powder, fused into glass blocks, sealed in air-cooled containers for around 50 years before being stored deep underground in a stable rock formation.

Front 35

Disposal of high level radioactive waste

Back 35

How do we get rid? The spent fuel rods are taken from the reactor and stored in cooling ponds with in the power station to allow most of the short-term radioactivity to die away. It is then transported to a processing plant. Here it is encased in steel containers and kept under water.

The cladding is eventually removed and the fuel rods are separated into unused uranium and plutonium and highly radioactive waste.

The uranium and plutonium is kept in sealed container for possible future use.

The waste is converted into powder, fused into glass blocks, sealed in air-cooled containers for around 50 years before being stored deep underground in a stable rock formation.

Front 36

Disposal of intermediate level Radioactive Waste

Back 36

How do we get rid? Sealed in steel drums that are encased in concrete and stored in buildings with reinforced concrete. Also stored deep underground in a suitable location that has a stable rock formation and low water flow.

Front 37

Disposal of low level radioactive waste

Back 37

How do we get rid? Sealed in metal drums and buried deep underground in a supervised repository. Treated cooling pond water is released into the environment.

Front 38

Temperature

Back 38

Temperature is a measure of the kinetic energies of the particles in the substance.

Front 39

Internal Energy

Back 39

The internal energy of a substance is due to the vibrations/movement energy of the particles (kinetic) and the energy due to the bonds holding them together (potential).

Front 40

Heat

Back 40

Heat is the flow of thermal energy and it flows from a high temperature to a low temperature.

Front 41

Nuclear Reactor Safety

Back 41

-Fuel Used

Using solids rather than liquids avoids the danger of leaks or spillages. They are inserted and removed from the reactor by remote controlled handling devices.

-Shielding

- Emergency Shutdown

Front 42

Fusion

Back 42

Solid into liquid

Front 43

Vaporisation

Back 43

Liquid into gas

Front 44

Ideal Gas Assumptions

Back 44

1. There are a very large number of molecules (N)

2. Molecules have negligible volume compared to the container

3. The molecules show random motion (ranges of speeds and directions)

4. Newton’s Laws of Motion can be applied to the molecules

5. Collisions are elastic and happen quickly compared to the time between collisions

6. There are no intermolecular forces acting other than when they collide

Front 45

Specific Latent Heat

Back 45

-the energy required to change 1 kg of a substance from solid to liquid or liquid to gas

-without a change in temperature.

Hint 45

Q=mL

Front 46

When driving frequency is less than nature frequency what is the phase difference

Back 46

0

Front 47

When driving frequency is less than nature frequency what is the phase difference

Back 47

0

Front 48

What is the phase difference when driving frequency is equal to natural frequency

Back 48

π

Front 49

What is the phase difference when driving frequency is greater than natural frequency

Back 49

π/2

Front 50

What happens when the driving frequency is lower than the natural frequency

Back 50

the oscillations have a low amplitude

Front 51

What happens when the driving frequency is the same as the natural frequency

Back 51

the amplitude increases massively, (maybe even exponentially).

Front 52

What happens when the driving frequency is higher than the natural frequency

Back 52

the amplitude of the oscillations decreases

Front 53

Coulomb’s law

Back 53

force between two (point) charges is proportional to (product of)charges and inversely proportional to the square of their distance apart

Front 54

What is the peak binding energy per nucleon?

Back 54

Peak 8.7 MeV per nucleon at 56 nucleons