Chapter 8 Radioactivity Flashcards
What is the largest radioactive source near earth?
Sun
Who discovered the X-ray
Willhelm Conrad Roentgen ( german physicist )
How was the x-ray discovered
Discovered unintentionally after WCR unintentionally took an x-ray photograph of his wife’s hand
Who discovered radioactivity?
Antoine Henri Becquerel ( french physicist )
How was radioactivity discovered?
Unintentionally produced rays that blacken a photographic plate even in the dark with a radioactive compound
Who discovered radioactive radiation?
Marie and Pierre Curie ( Polish )
What award was given to Conrad Roentgen and Henri Becquerel?
Nobel Prize in Physics
How did Marie Curies die?
Died to prolong exposure to gamma rays
What is radioactivity?
A random and spontaneous decay process of an unstable nucleus by emitting radioactive radiation
Examples of forms of radioactive radiation
Alpha particles
Beta particles
Gamma rays
What is radioactive decay
A random and spontaneous decay of an unstable nucleus emitting radioactive radiation until the nucleus becomes more stable
Examples of radioactive radiation
Carbon 14
Thorium-234
Uranium-238
Radon-222
What is the first unit of radioactivity introduced
Curie ( Ci )
How many decays per second is 1 Curie
3.7 x 10{10} Decays per second
What is the current S.I unit for radioactivity
Becquerel ( Bq )
Presence of radioactive radiation can be detected using what?
Cloud chamber
Geiger-Muller counter
Dosimeter
How many Curie is 1 Becquerel?
3.7 x 10 {-4} Ci
What is half-time?
Time taken for the number of undecayed nuclei to reduce to half of its original value
Describe Dalton’s Atomic Theory
States that an atom is the smallest particle and cannot be further divided
How to know if an atom is neutral?
If the number of protons and neutrons in an atom is the same
What is an ion?
It is a charged atom when it gains or loses an electron
What is a cation?
An atom that loses electrons and forms a positive ion
What is an anion
An atom that gains electrons and forms a negative ion
What is ionising radiation?
When radiation such as radioactive radiation passes through air and produces positive and negative ions
Examples of ionising radiation
Xray
Gamma ray
Example of non-ionising radiation
Radio
Infrared
Microwave
Visible light
Ultraviolet
natural characteristic of Alpha, Beta and gamma rays
Helium Nucleus
High speed electron
Electromagnetic wave
charge of particle of Alpha, Beta and gamma rays
Positive
Negative
Neutral
Ionising power of of Alpha, Beta and gamma rays
High
Moderate
Low
Penetration power of Alpha, Beta and gamma rays
Low
Moderate
High
Deflection by magnetic field of Alpha, Beta and gamma rays
Upwards
Downwards
Straight
categories of sources of ionising radiation?
Natural
Man-made
Examples of natural radiation
Cosmic Rays
Background radiation
Examples of man-made radiation
Nuclear Tests
Nuclear accidents
Use of radioisotope for medical purposes
What are cosmic rays?
High-energy radiation produced outside the solar system or from another galaxy
What is background radiation?
Made up of various types of ionising radiation in the environment
Sources of background radiation?
Cosmic rays
Radioisotopes for medical use
Radioactive waste from nuclear accidents/tests
Biological effect from ionising radiation is measured in a quantity of?
Dose
1 dose of 1 Sv equals to how many joules of ionising radiation which is absorbed by how much living tissue?
1 Joule
1 Kilogram
What is the unit of background radiation does used?
microSievert/hourr
What is a safelevel of ionising radiation?
less than 0.2 uSv/h
< 0.0002 mSv/h
1752 uSv/year
1.752 mSv/year
Uses of radioactive radiation?
Archeology and geology
Monitoring thickness of metal sheets
Agriculture
Defense
Food Preservation
Medical
What is the method used to determine the age of fossil using radioactive radiation?
Carbon-14 dating
How is carbon-14 used to measure the age of remains?
C-14 in tissues begins to decay and emit beta radiation with a half life of 5700 years. By measuring the activity of C-14, the age of remains can be determined
Who used carbon-14 dating?
Archeologist and Geochronologists
How is radioactive radiation used to monitor the thickness of metal sheets?
A metal sheet is passed in between a beta radiation detector and a beta radiation source. If it detects too much beta radiation, the metal sheet is too thin
What is radioactive radiation used for in agriculture?
Kill beetles
Control population of pests by sterilization
Determine the best type of phosphate fertilizer
Modify characteristics of plants
How do we determine the best type of phosphate fertilizer for plants?
the rate at which beta radiation is emitted during the nuclei delay of phosphurus-32 is used to determine the absorption rate of phosphate fertilizer in plants
How is radioactive substances used in the field of defence?
Nuclear bomb
What logo is used to label food preserved with radioactive radiation?
The radura logo
Uses of radioactive radiation in the medical field?
Kill cancer cells ( Caesium-137 or Cobalt-60 )
Determine location of blood clots ( Sodium-24 )
Treat tumours in the brain ( Technetium-99 )
Destroy germs ( Cobalt-60 )
Treat thyroid glands ( Iodine-131 )
Examples of safety measures when handling radioactive sources and radioactive wastes
Shield radioactive substances with thick slabs of lead
Store radioactive sources in containers with thick lead walls
Use of robotic hands
Wearing appropriate protective clothing
Disposal of radioactive waste done correctly
