Nuclear Radiation Flashcards
How do you draw a line of best fit on a count-rate graph?
Curved-line.
Why are articles in scientific journals generally more trustworthy than articles in newspapers?
Because they are peer reviewed.
Why is it difficult to detect gamma radiation?
Because it is weakly ionising.
Explain why the count rate was less than the activity of the sample of lanthanum-140
Because radiation spreads out in all directions.
So only some of the radiation goes into the GM tube.
How does a GM tube detect radiation?
The greater the level of radiation, the _________________ in the tube so the greater the _____________________.
more ionisation
number of counts
Why does the teacher stand as far away from the apparatus while in the practical?
To reduce the amount of radiation received.
Why would irradiated food not become radioactive?
Because the source of radiation is not in the food.
What is the structure of alpha and beta particles?
Alpha particles consists of 2 protons and 2 neutrons.
A beta particles are an electron, the particle is emitted from the nucleus.
Why is alpha radiation the most ionising?
Because alpha particles have a charge of +2.
They are heavy particles.
What is the penetration of alpha and beta particles?
Alpha particles are very _________________.
Alpha particles can penetrate a _________ in air.
Beta particles can penetrate for a _______ in air.
Beta particles can travel ___________ than alpha particles.
poorly penetrating
few cm
metre
further
How do alpha particles and beta particles deflect in an electrical field and why?
Alpha particles and beta particles are deflected in opposite directions in an electric field.
Beta particles are deflected more than alpha particles.
So Beta particles have much less mass.
Describe the process of nuclear fission: (4)
A neutron is absorbed by the __________.
This forms a _______________ that is _________.
The larger nucleus splits into _____________________.
Releasing __________________.
nucleus
larger nucleus
unstable
two smaller nuclei
neutrons and energy
What is half life?
The average time taken for number of nuclei to halve.
Explain why it is sometimes necessary for scientists to replace a scientific model. (2)
New __________________ is obtained, which cannot be ___________ by the _________.
scientific evidence
explained
model.
Most of the alpha particles went straight through the oil, so:
Most of the atom is empty space.
