3.5 Nuclear Decay Flashcards
Describe briefly how Rutherford carried
out his alpha scattering experiment.
Rutherford directed a stream of high
speed alpha particles at a very thin sheet
of gold foil and observed how these
particles were affected by it.
What was the expected outcome of
Rutherford’s experiment?
Most of the alpha particles were
expected to pass straight through the foil
with very little deflection.
What was observed by Rutherford?
● Most particles passed through with no deflection.
● Some particles were deflected by large angles.
● A few particles were deflected by more than 90 degrees.
What conclusion can be drawn from the
observation that most particles passed
straight through?
In can be concluded that most of the atom must be empty space.
What conclusion can be drawn from the
observation that some particles were
deflected by large angles?
It suggests that the centre of the atom
must have a large positive charge which
can repel these particles.
What conclusion can be drawn from the
observation that some particles were
deflected by more than 90 degrees?
It suggests that the centre of the atom must be very small but also very dense since it changed the direction of fast-moving particles.
Name 3 types of radiation.
- Alpha
- Beta (plus and minus)
- Gamma
Order alpha, gamma and beta radiation starting with the most ionising.
● Alpha
● Beta
● Gamma
Order alpha, gamma and beta radiation starting with the most penetrating.
● Gamma
● Beta
● Alpha
A sheet of paper can block which type of radiation?
Alpha radiation.
When a nucleus decays through gamma
radiation, how does the atomic number
and mass number change?
They remain the same as the number of
protons and neutrons remains constant.
Why is ionising radiation seen as dangerous?
Ionising radiation can kill or mutate cells,
which could lead to mutations and cause
conditions such as cancer.
Which radiation is more harmful inside a human body, alpha or gamma?
Alpha radiation - because it has a high ionising power so it would damage more cells. It is also very poorly penetrating, therefore it is not be able to leave the body, whereas gamma radiation is highly penetrating.
Give an example of a real life use of
Beta decay and explain why Beta is
chosen for this.
Beta radiation can be used to measure the thickness of paper or aluminium foil. Alpha isn’t used as it is less penetrative and wouldn’t reach the detector on
the other side of the sheet. Gamma radiation is too penetrative and would pass through everything.
Which type of radiation follows the inverse square law?
Gamma radiation.
Derive T 1/2 = ln(2)/𝜆
