Nuclear Physics

Nuclear fission

The division of large unstable nuclei into smaller nuclei

Nuclear fission

two light nuclei fuse to become a single larger nuclei,

Radioactive decay

When an unstable nucleus decays

Nuclear radiation

Particles emitted from radioactive decay.

What are the deductions of the rutherford experiment

The nucleus has a positive charge concentrated in a small region, its dense and the mass of the atom is concentrated in it. The rest of the atom is mostly empty space.

Why was gold used in the Rutherford experiment?

Gold is unreactive and has large atoms

Why did the gold foil used in the Rutherford experiment have to be thin?

Alpha particles have low penetration power, the gold is thin to avoid alpha particles from being absorbed by the foil.

Why is it necessary to remove the air from the chamber in a Rutherford experiment?

Alpha particles have low penetration power, removing the air will prevent deflection or absorbption of alpha particles by air molecules

Why does the alpha particle beam have to be narrow?

It has to be narrow so that the angle of deflection is measured accurately.

How do we measure how well radiation can ionise atoms?

Ionisation chambers

How do Ionisation chambers work?

A cylindrical chamber is filled with gas. The atoms are then ionised by the ionising radiation and ions and delocalised electrons are formed. The more ions there are, the more electrons there are at the anode, and therefore a greater current is recorded.

How do we determine between alpha and beta particles

Cloud chambers

Do gamma waves make a trail in a cloud chamber

No

Between alpha and beta particles, which particle makes the longer and more curved trail in the cloud chamber?

Beta particle

How are photons released from the nucleus during electron capture?

After electron capture, an outer shell electron falls to an inner shell electrons place to replace the captured electron. A photon that has a frequency that corresponds to the electron’drop in quantum shell is emmitted, 

Is radioactive decay random?

Yes

Can we predict when a nuclei will decay

No

What is the definition of the decay constant (lambda)

The probability of a single nucleus decaying per unit time

What is the definition of Activity:

Number of nuclei that decays per unit time.

How do we calculate the energy released during radioactive decay?

Energy of decay particle multiplied by the activity of the source

What can ionising radiation cause?

Radiation burns, increased risk of cancer, damaged DNA, damaged cells which could lead to cell death,

What is the definition of radiation dose

The amount of energy transferred to someone per unit mass, from a radioactive source ( meausured in Sv or J/kg)

What is a film badge

A badge worn by people who frequently work in areas of high radiation which is used to monitor the amount of radiation the worker is exposed to.

What do film badges contain

Photographic film, Plastic filters, Aluminium plates,

Binding energy