Nuclear Reactions and Radiation Concepts

Fill in the blank: The rate of decay of the radioactive nuclei in a given isotope is called ________. It is proportional to the total number of nuclei in the sample and is measured in Becquerels.

• Activity

• Half-life

• Mass number

• Atomic number

Fill in the blank: The emission of an alpha particle (2 protons and 2 neutrons) from an unstable nucleus to make it more stable is called ________. Alpha radiation is strongly ionising and is stopped by a few centimetres of air or a sheet of paper.

• Alpha Decay

• Beta Decay

• Gamma Emission

• Neutron Capture

Fill in the blank: A unit used to express atomic masses is called ________. One AMU is equal to the one twelfth of the mass of a carbon atom.

• Atomic Mass Unit

• Mole

• Gram

• Dalton

Fill in the blank: Radiation that is found in small quantities all around us and originates from natural sources such as rocks and cosmic rays as well as man-made sources such as nuclear accidents and medical sources is called ________.

• Background Radiation

• Gamma Radiation

• Alpha Radiation

• Ultraviolet Radiation

Fill in the blank: The emission of a beta particle when a proton turns into a neutron (or vice versa) in an unstable nucleus is called ________.

• Beta Decay

• Alpha Decay

• Gamma Emission

• Electron Capture

Fill in the blank: The amount of energy required to split a nucleus into all its separate constituent nucleons is called ________. It is equivalent to the mass defect.

• Binding Energy

• Ionization Energy

• Activation Energy

• Fusion Energy

Fill in the blank: The process of the neutrons released by a fission reaction inducing further fissile nuclei to undergo fission is called a ________.

• Chain Reaction

• Fusion Reaction

• Radioactive Decay

• Thermal Expansion

Fill in the blank: A method of estimating a nuclear radius by firing an alpha particle at it and calculating the distance at which all the alpha particle’s kinetic energy is converted to electric potential energy is called ________.

• Closest Approach

• Photoelectric Effect

• Nuclear Fission

• Compton Scattering

Fill in the blank: The introduction of radioactive material to another object, making the object radioactive, is called ________.

• Contamination

• Irradiation

• Fusion

• Fission

Fill in the blank: Rods found in nuclear reactors to absorb neutrons and control the rate of reaction are called ________. They can be raised or lowered depending on the rate required.

• Control Rods

• Fuel Rods

• Moderator Rods

• Coolant Rods