physics

Created by

sage flynn

Cards (64)

Density = mass / volume 
In kg/m^3
How do measure the density of a solid object or liquid ?
Measure its mass (weigh it) and its volume, then use the density equation p=m/v
What does rearranging the density equation give you
M=p/v or v=m/p
For object that have a lower density than water, do they float ?
Yes they float
Solid to a liquid is what process
Melting
Process of liquid to solid
Solidifying / freezing
Solid to gas is called ?
Sublimation
Gas to liquid is called ?
Condensation
Gas to a solid is called ?
Condensation
Liquid to gas it called ?
Vaporisation / boiling
When drawing a solid (in the weird box thingy) what must be happening 
The partials must all be touchin .. best to put 9 'o' 's
When drawing a liquid (in the box thing magigy) what must it be doing
The partials must me 50% touching
What drawing a gas (in the weird box) what must it look like ?
None touch, they spread to fill the container
Pneumonic for density =m/v 
Dinner = meat /veg
What is the internal energy of an object 
How much energy the particles have
Properties of alpha radiation...
Description: IT IS A PROTON AND NEUTRON NUCLEUS

Mass: 4

Charge: +2

Range of effectiveness in air: 2 - 5 CM

Stopped by: PAPER, LEAD ETC (ANY LAYER BARRIER)

Ionizing power: PRETTY HIGH BUT CAN'T PENETRATE

Detected by electric or magnetic field: YES
Properties of beta radiation...
Description: IT IS AN ELECTRON FROM THE NUCLEUS

Mass: 0

Charge: -1

Range of effectiveness in air: 15 - 20 CM

Stopped by: 1/2 CM OF ALUMINIUM

Ionizing power: MEDIUM - HIGH BUT CAN PENETRATE

Detected by electric or magnetic field: YES
Properties of gamma radiation...
Description: IT IS AN ELECTROMAGNETIC WAVE FROM THE NUCLEUS

Mass: 0

Charge: 0

Range of effectiveness in air: SEVERAL METRES

Stopped by: THICK LEAD

Ionizing power: VERY LOW BUT HIGH PENETRATION

Detected by electric or magnetic field: NO
How to check for radiation and how does it work?
You use a Geiger counter.

This is made up of a detector called a Geiger Muller tube that is connected to an electronic counter.

The counter clicks each time a particle of radiation from a radioactive substance enters the Geiger Muller tube.
Why are some substances radioactive?
Atoms of a radioactive substance have a nucleus that is unstable. It is described as decaying.

An unstable nucleus becomes stable or less unstable by emitting alpha, beta or gamma radiation.
What is plum pudding model?
What is Bohr's model of the atom?
What are isotopes? 
Atoms of the same element with different number of neutrons.
What is neutron emission?
It is when neutrons are emitted by some radioactive substances as a result of alpha particles colliding with an unstable nuclei in the substance.

This causes the unstable nuclei to become more unstable and emit a neutron. They can pass through substances more easily than other radiation.
What is the half life of a radioactive isotope?
It is the average time it takes for the number of nuclei of the isotope to be halved.
What is the equation for the count rate after a number of half lives?
count rate n lives = the initial count rate / 2 n
Radioactive decay equations... 
Alpha decay -
²²⁶₈₈Ra → ²²²₈₆Rn + ⁴₂He

Beta decay -
²¹⁸₈₄Po → ²¹⁸₈₅At + ⁰₋₁e

Gamma decay -
²¹⁸₈₅At → ²¹⁸₈₅At
What are medical tracers?
Type of radiation - Gamma (contamination)

Description - Used to trace flow of substance through organ. Contains radioactive isotope that emits gamma radiation.

Why is this radiation used - Can be detected outside the system.
What are imaging/gamma cameras?
Type of radiation - Gamma (contamination)

Description - It takes a digital image of the radioactive isotopes which are absorbed by a specific organ. The gamma radiation from the isotopes are detected by the camera.

Why is this radiation used - Penetrates the body to allow the camera to see specific body parts.
What is external radiotherapy?
Type of radiation - Gamma (contamination)

Description - Narrow beam of gamma radiation penetrates the body.

Why is this radiation used - Can penetrate the skin.
What is internal radiotherapy?
Type of radiation - Beta (contamination)

Description - Implants given to destroy cancer cells.

Why is this radiation used - Can penetrate and is relatively strong.
How is beta radiation used to manufacture paper or any other layer of material?
When paper is manufactured, it is important to get the thickness right.

Beta passes through paper and is detected on the other side.

The thicker the sheet, the weaker the beta radiation will be after passing through.

This can control rollers.
How is alpha radiation used to detect smoke?
Alpha radiation is easily stopped and this makes it useful to smoke alarms.

Americium-241 is often used as the source of alpha radiation.
How is gamma radiation used to see if there are any cracks inside welds? 
For instance, when industrial boilers are made, pipes, tubes and plates are welded together.

Gamma radiation is used to see if there are any cracks inside welds using a gamma radiation source known as iridium-192 and photographic film.
How is gamma radiation used to find liquids and gases? 
For instance, iridium-113 can be added to power station cooling water in tiny quantities.

By looking at the gamma radiation it gives off, scientists can tell where and how fast the cooling water has traveled through the many pipes in the power station.
What is nuclear fission? 
It is a process of splitting of a heavy atomic nucleus such as that of uranium and or plutonium using a neutron beam.

The process is accompanied by the release of a large amount of energy, in the form of gamma radiation, plus the kinetic energy stored in the fission neutrons.
Inside a nuclear reactor...
What is a chain reaction regarding nuclear fission?
When a fission event causes more fission events to happen in a nuclear reactor.
What is nuclear fusion?
When two small nuclei release energy when they are fused together to form a single larger nucleus.

It requires very high temp to overcome the high forces of electrostatic repulsion.

An example of nuclear fusion is when hydrogen nuclei fuse to form helium nuclei in turn, releases enormous amounts of energy.

This is how the Sun produces energy we receive as electromagnetic radiation.
What is the fusion word equation?
hydrogen + deuterium → photons → helium