Modern Physics - Nuclear Physics - SS2 Physics Past Questions and Answers - page 3
Which type of radiation has the longest wavelength and the lowest frequency?
Alpha radiation
Beta radiation
Gamma radiation
None of the above
Which type of radiation has the highest energy and can cause ionisation in matter?
Alpha radiation
Beta radiation
Gamma radiation
None of the above
Describe the properties and characteristics of alpha radiation. How does it interact with matter? Discuss its ionising power and range.
Alpha radiation consists of helium nuclei, which consist of two protons and two neutrons. It has a positive charge and is relatively heavy compared to other types of radiation. Due to its size and charge, alpha particles have low penetrating power and are easily stopped by a few centimetres of air or a sheet of paper. They have high ionising power and can cause significant damage to living tissues when emitted from a radioactive source.
Explain the nature and behaviour of beta radiation. Discuss the composition of beta particles, their charge, and their ability to penetrate matter.
Beta radiation consists of high-speed electrons or positrons. Beta particles can be negatively charged (electrons) or positively charged (positrons). They have a much smaller mass compared to alpha particles, and therefore, they have greater penetrating power. Beta particles can be deflected by electric and magnetic fields and can travel several metres in the air. They have moderate ionising power and can penetrate into living tissues, causing damage.
What does the term "half-life" refer to in radioactive decay?
The time it takes for half of the radioactive sample to decay.
The time it takes for all the radioactive atoms to decay.
The time it takes for the radioactive decay to double.
The time it takes for the radioactive decay to halve.
Which of the following statements about half-life is true?
The half-life of a radioactive substance is constant and does not change.
Different radioactive isotopes have the same half-life.
The half-life of a radioactive substance can be altered by external factors.
The half-life of a radioactive substance depends on its temperature.
How can the concept of half-life be used in radioactive dating?
By measuring the remaining half-life of a radioactive sample.
By comparing the half-life of different radioactive isotopes.
By determining the ratio of parent isotopes to daughter isotopes.
By calculating the rate of radioactive decay.
Which of the following isotopes is commonly used for radiometric dating of organic materials?
Uranium-238.
Carbon-14.
Potassium-40.
Radium-226.
Radiocarbon dating is primarily used to determine the age of:
Fossils.
Rocks.
Ancient pottery.
Meteorites.
Explain the concept of half-life in radioactive decay. How is it determined experimentally, and what does it signify?
The concept of half-life refers to the time it takes for half of the radioactive atoms in a sample to decay. It is a characteristic property of a radioactive isotope. The determination of half-life involves measuring the decay of a radioactive sample over a period of time. By plotting the decay curve and analysing the data, the half-life can be calculated. It signifies the rate at which radioactive decay occurs and provides a measure of the stability or instability of a radioactive material.