TOPIC 10: NUCLEAR RADIATION

Define radioactivity

The process of the decay of a radioactive nuclide (i.e. the emission of energetic particles/waves from the nucleus of an atom)

Define Natural

Not induced (i.e. nothing has to be done to radioactive minerals to make radioactivity happen, and nothing can be done to stop it).

Define Spontaneous

Nothing can be done to change the amount of radiation emitted (e.g. heating the material, putting it in electric/magnetic fields or putting pressure on it).

Define Random

There is no way of telling when a particular nucleus will decay - the emission of radiation is completely irregular.

Define Half life

the time taken for the number of undecayed nuclei to halve from an original value

What is the decay constant

the probability that the nucleus will decay for each second that it exists

Define Activity

the number of unstable radioactive nuclei that decay per second

What is the equation for activity

A=-λN

What else can the equation for activity be written as?

N=N0 e^{-λ t}

Define background radiation

Background radiation is the ionizing radiation present in the environment. Background radiation originates from a variety of sources, both natural and artificial.

What are the main sources of background radiation

• Radon gas- largest

• medical

• ground and buildings

• cosmic rays

• food and drink

• nuclear and other.

What is background radiation measured in

Becquerels (Bq)

What is gamma Emmision

A

What is a beta emission

What is a beta emission

What is radioactive decay

why does the radioactivity of a source decrease over time

radioactive decay is a random and spontaneous process. As more time passes, more nuclei decay, therefore there are less unstable nuclei left to decay as time goes by, meaning activity slows down. 

Define Radiation

Why is the count rate different from the activity

Not all of the isotopes will go in the direction of the Geiger Muller counter when measuring count rate.

What is the equation for half life

T1/2= Ln2/λ

What does N stand for in A=-λN

N is the number of radioactive particles present in the source at time t

What is the unified atomic mass u

The unified atomic mass unit is a standard unit of mass that quantifies mass on an atomic scale.

What is the value of U

1 u = 1.66×10⁻²⁷ kg

Rank the types of nuclear decay from least to most ionising

Rank the types of nuclear decay from least to most penetrating

Rank the types of nuclear decay from least to most range

Rank the types of nuclear decay from fastest to slowest.