radioactivity-p7

• Who proposed the plum pudding model of the atom?


  JJ Thompson
• What did Ernest Rutherford discover about the atom?


  The positive part of the atom is concentrated in a small nucleus
• What are the two types of particles found in the nucleus?

  Protons and neutrons
• What is the atomic number of an element?


  The number of protons in the nucleus
• What is an isotope?


  Atoms of the same element with different numbers of neutrons
• What is radiation?


  Any particle or wave emitted by something
• What type of radiation is emitted by the nucleus of an atom?

  Gamma radiation
• What is alpha decay?


  A process where a nucleus emits two protons and two neutrons
• What is the atomic number and mass of an alpha particle?


  Atomic number 2 and mass 4
• What happens to the atomic number during alpha decay?


  It decreases by 2
• What is beta decay?


  A process where a neutron turns into a proton and emits an electron
• What is the charge of a beta particle?


  • 1
• How does alpha radiation interact with matter?


  It has high ionizing ability but is easily stopped
• What is background radiation?


  Radiation from natural and man-made sources in the environment
• How do you calculate corrected radiation count?

  By subtracting background count from the count with the source
• What is the penetrating power of beta radiation?


  It can pass through a few millimeters of aluminum
• What is gamma radiation used for?


  For radiotherapy and sterilizing medical equipment
• What is radioactivity?


  The rate of decay of a radioactive source
• How is radioactivity measured?


  By using a GM tube to count radiation over time
• What is half-life?


  The time it takes for the number of unstable nuclei to halve
• How do you find the half-life from a decay graph?


  By halving the initial number and measuring the time taken
• What happens during nuclear fission?


  A nucleus splits into two daughter nuclei, releasing energy
• What is the relationship between mass and energy in nuclear reactions?


  Mass can be converted into energy
• What is a chain reaction in nuclear fission?


  A process where released neutrons cause further fission events
• How does nuclear fusion occur in the Sun?


  Two light nuclei combine to form a heavier nucleus, releasing energy
• Why is it difficult to create a viable fusion reactor?


  Because scientists have not harnessed enough energy from the process
• What is the specific latent heat of vaporization for water?


  2,260,000 J/kg
• What is the significance of internal energy in a substance?


  It is the sum of the kinetic and potential energy of all particles
• How does the kinetic energy of particles change with temperature?


  An increase in temperature results in an increase in kinetic energy
• What is the role of neutrons in nuclear fission?


  They can initiate further fission reactions by colliding with other nuclei