PERSONAL Question & Gaps Correction Deck

• You can't use a radioactive isotope with a half life of 15 hours to date a rock because the half life is too short and all of the isotope would be decayed already, and because the decay occurs so quickly it'd be indistinguishable from background radiation.
• Question 3c)

  • Activity of a sample is due to the nucleus decaying / being unstable / changing into a new isotope / emitting gamma radiation
  • Fewer radioactive nuclei are left
  • This means the number of nuclei decaying per second decreases
• Why does a volmeter show a reading when you pass a magnet through a coil of wire attached to a circuit with a volmeter, There is voltage because:

  • There is potential difference because of the change in magnetic flux [1]
  • The magnetic field through the coil is changing [1]
  • This leads to induced voltage [2]
• Which one of these is NOT a valid answer to making the pointer of an sensitive ammeter move to another direction?

  1. Flip the coils around
  2. Reverse the connections of the Ammeter
  3. Move magnet out (as opposed to in) or vice versa (in as opposed to out) of the coil
  4. Swap the poles around

  Flip the coils around
• (ii) Describe how the risks of working with radioactive sources can be reduced.

  • Reduce exposure time; [1 mark]
  • Handle with tongs/use robotic handling/keep at a distance; [1 mark]
  • Use shielding / work in fume cupboard; [1 mark]
  • Wear film badge / monitor; [1 mark]
• (ii) Explain what is meant by fission products (2 marks):

  • (Particles) formed after fission / after uranium breaks up; [1 mark]

  Give an example of a fission product:

  Any one from:

  • Neutron; [1 mark]
  • Daughter nuclei; [1 mark]
  • Named products such as Xenon; [1 mark]
• (iii) Explain why it is important to contain these fission products:

  Any one from:

  • The products are (still) radioactive; [1 mark]
  • The products emit ionising radiation; [1 mark]
  • The products are harmful to people / the environment; [1 mark]

  Explain why this containment must be for a long time:

  • The products last for a long time / have a long half-life; [1 mark]
• Uranium 238 is the most common isotope of uranium because it has the longest half life
• the three products of fission of uranium nuclei are daughter nuclei, neutrons, and gamma radiation / thermal energy
• When a control rod is removed from the reactor:

  • Rate of reaction increases
  • Fewer neutrons absorbed by control rod / more neutrons collide with uranium
  • Temperature increases
• Explain why it is difficult to make the surrounding area safe again after a serious nuclear accident:

  • The radiation is harmful / presents a danger to life
  • The radioactive material has high activity levels
  • It can be difficult for workers to access the area, making it more difficult to clean up
  • There will be a need for special handling equipment / there is a difficulty in removing material
  • There may need to be an extensive time for radiation levels to reduce
  • Radioactive material can mix with the local environment and be hard to remove
  • Material may be spread far beyond the accident site
• What are the limitations of radiocarbon dating?

  1. assumes level of cosmic radiation is constant, this can be remediated by using objects of known age
  2. limited to 60 000 years
• perent nuclide
• decays into thorium 234 -> lead-206 (stable), so the more lead-206 the older it is
• The tension force of a cable holding up a block and the force of the blocks own weight being of equal magnitude and in opposite directions is NOT an example of newtons third law because?

  The forces are acting upon the same body and do not have the same type and source/
• For the two wires attracting question in past paper 2023 Jan 2P:

  1. Both wires have magnetic field around them
  2. Each wire has a current in a magnetic field
  3. Each wire experiences a force that is the same size but in opposite directions
• For the two wires attracting question in past paper 2023 Jan 2P:

  1. RH Grip rule indicates relationship between current and field for one of the wires
  2. LH rule indicates relationship between field from one wire, current in other wire, and force on second wire
  3. Combination of these two will give force on second fire towards first wire
• For the question about how the different wavelengths of light from the binary system in past paper 2023 Jan 2P as to how this is evidence for the big bang theory:

  • light (from galaxy) has been red-shifted
  • {binary system / galaxy} is moving away (from Earth);
  • universe is expanding
  • (therefore) universe must have been at a single point some time in the past;
• How does a graph showing that wavelength increases with distance show that the universe is expanding?

  1. red shift, the wavelengths are increasing with distance
  2. recession/velocity increases with distance from earth or milky way
  3. galaxies are moving away from each other but not by them moving in space but because space itself is expanding, increasing the distance between them
• Air will gain more heat when transferred from water than water will lose because air has a lower specific heat capacity.
• The shortest wavelength colour is violet
• Bar chart data should be used for categoric data (also because data is discontinuous)
• what is the equation that links input voltage, output voltage, turns in primary coil, and turns in secondary coil?

  input voltage / output voltage = turns in primary coil / turns in secondary coil
• Using a high voltage increases the efficiency of transmission because of the equation P = VI proving that as power stays the same and voltage increases current decreases which reduces heating.
• To explain why a voltage is induced:

  • Changing magnetic field / flux / field lines (due to the motion of the magnet)
  • Changes within the coil / cuts the coil
• Sources of background radiation:

  Radiation from radon gas

  Cosmic radiation

  Radiation from medical sources / equipment

  Nuclear waste / accidents

  Some foods (example: banana)
• frequency = 1/time period
• wavespeed (m/s) = wavelength (m) x frequency (Hz
• Transverse waves have oscillations that are perpendicular to the direction of energy travel.
• Longitudal waves have oscillations that are parallel to the direction of energy transfer.
• longitudinal waves need a medium to continue moving forward. This is because longitudinal waves, sometimes called compression waves, require matter to compress and rarefy in order for the wave to propagate itself in the direction the wave travels.
• Gamma waves are used to sterilised medical equipment by killing bacteria.
• Order of EM spectrum (ascending frequency, descending wavelength)

  1. Radio waves
  2. Micro waves
  3. Infared
  4. Visible light
  5. Ultraviolet
  6. X-rays
  7. Gamma rays
• In vacuum, speed of electromagnetic waves = 3 x 10 ^ 8
• Why do sound and radio waves have different frequencies despite having the same wavelength ?

  Recall the speeds of sound and radio waves:

  • Sound travels at 330 m/s while radio waves travel at 3.0 × 108 m/s

  Draw a conclusion:

  • Since the two waves travel at different speeds
  • They travel the same distance/one wavelength in different times
• in the doppler effect wave fronts are closer, wave crest distance decreases, wave speed formula (& wavelength stays the same) so frequency perceivably goes up.