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Y10 Physics – Radioactivity etc
1. Explain what happens in
radioactive decay.
4. State what each of the three
types of radioactivity is made
up of.
7. Describe what happens in
ionisation and why this is
damaging to the human body.
10. Describe the similarities
and differences between two
isotopes of the same element.
13. Describe what is meant by
the ‘specific heat capacity’ of a
substance.
2. State the ranges in air for
alpha, beta and gamma.
3. State the unit for radioactive
decay.
5. State what each type of
nuclear radiation can be
absorbed by.
6. Explain why a beta source is
more suitable than gamma or
alpha for monitoring paper
thickness.
8. Explain why alpha particles
are strongly ionising.
9. State what is meant by the
atomic number and atomic
mass of an atom
11. Describe the change in mass 12. Describe the change in mass
and proton numbers when an
and proton numbers when an
alpha particle is emitted.
alpha particle is emitted.
14. Explain how the density, of
particles is different in solids
and gases but mass is not.
15. Explain how the energy and
movement of particles is
different in solids and gases.
Y10 Physics – Radioactivity etc – Answers
1. Unstable nucleus of an atom breaks up (decays) and releases particles or radiation.
2. Alpha – a few cm
Beta – 0.5 – 1.0 m
Gamma – many km
3. Bequerel – Bq - (counts per second)
4. Alpha – 2 protons, 2 neutrons (helium nucleus)
Beta – electrons
Gamma – electromagnetic radiation
5. Alpha – by thin card
Beta by 5mm aluminium
Gamma – reduced by thick lead/concrete
6. Paper will absorb some of the beta but not all of it, so the amount of beta getting through
changes with the paper thickness
7. Radioactivity collides with an atom and knocks away an electron – damage dna in cells in
the body.
8. They have a high mass – more likely to collide with atoms.
9. Atomic number= number of protons (=no. of electrons); atomic mass=no. protons+neutrons
10. Same number of protons; different number of neutrons
11. The atom loses two protons and two neutrons – proton number down by 2; mass number
down by 4
12. A neutron decays into a proton and electron; proton number increases by 1; mass number
stays the same.
13. The change in thermal energy to raise the temperature of 1kg by 1oC
14. The density in solids is greater than gases – particles are more spread. The total number of
particles cannot be created or destroyed.
15. The particles in a gas have more energy; move fast and freely in random directions.