. Flashcards
What other particle is also emitted during beta-plus decay
An electron neutrino
What changes occur to the nucleus during beta-minus decay
A neutron changes into a proton
What is required to block beta radiation?
A few millimetres of aluminium
What type of nuclear radiation is not deflected by a magnetic field?
Gamma
What is required to block alpha radiation?
A thin sheet of paper/skin
What changes occur to the nucleus during beta plus decay?
A proton changes into a neutron
What happens to the values of A and Z during beta-plus decay?
A remains the same, Z decreases by 1
What did J.J. Thompson discover in 1897?
Electrons
What happens to the values of A and Z during beta-minus decay?
A remains the same, Z increases by 1
What is the range of gamma radiation in air?
Unlimited
What experiment led to the development of the nuclear model of the atom?
Rutherfords alpha scattering experiment?
What is the relationship between the intensity of gamma radiation and distance from the source?
Inverse square law
What is an alpha particle the same as?
A helium nucleus
In a cloud chamber, many straight tracks are produced, all with a length of 4cm. Which type of radiation is observed?
Alpha radiation- all emitted alpha particles have the same kinetic energy.
What happens to the values of A and Z during alpha decay?
A decreases by 4, Z decreases by 2
What other particle is emitted during beta minus decay?
An electron antineutrino
What changes occur to the nucleus during alpha decay?
The nucleus loses tow neutrons and two protons
In a cloud chamber, wispy, curled tracks are produced. Which type of radiation is observed?
Beta radiation
Describe the plum pudding model of the atom
Negatively charged electrons embedded in a cloud of positive matter.
What is required to block gamma radiation?
A few centimetres of lead or a few meters of concrete.
Why is ionising radiation harmful?
It can destroy cell membranes and damage DNA
What particles make up an alpha particle?
Two protons, two neutrons
What is a beta plus particle?
A fast moving positron produced in and emitted from the nucleus
State three human caused sources of background radiation.
Medical, buildings, food, nuclear weapons, air travel, nuclear power
What is a gamma ray?
A high energy electromagnetic wave (or photon)
How do you carry out a corrected count rate (in seconds)
Measure the number of counts detected with the source in place in a certain period of time, then take away the number of counts detected when the source is not present in the same time. Divide the answer by the time.
What changes occur to the nucleus during gamma decay?
The nucleus loses energy
Describe the nuclear model of the atom
A positively charged nucleus surrounded by negatively charged electrons.
What is the range of alpha radiation in air?
A few centimetres
What is a beta minus particle?
A fast moving electron produced in and emitted from the nucleus
Which type of nuclear radiation is deflected most by a magnetic field?
Beta
What happens to the values of A and Z during gamma decay
No change
State 3 natural sources of background radiation
Radon gas, rocks, cosmic rays
What is the range of beta radiation in air?
Up to around a metre (depending on initial kinetic energy)
what is binding energy?
It is the energy required to separate an atomic nucleus into its individual protons and neutrons.
what is nuclear fission?
It is when a nucleus splits into two or more smaller parts, releasing energy.
what is a thermal neutron
It is a slow moving neutron or low kinetic energy neutron.
They are in thermal equilibrium with the moderator.
