Physics 1-4 Questions & Answers

Physics 1-4 Questions & Answers (P1) Define system - ANSWER: A system is an object or group of objects (P2) What are the circuit symbols - ANSWER: (P3) Define density - ANSWER: The mass per unit volume density (P4) What is the atomic structure - ANSWER: Positively charged nucleus surrounded by negatively charged electrons Alpha decay causes . . . - ANSWER: . . . both the mass and charge of the nucleus to decrease Are changes of state physical or chemical changes - ANSWER: They're physical changes and are reversible. They aren't chemical because the material retains its original properties when reversed Beta decay causes . . . - ANSWER: . . . the charge of the nucleus to increase but doesn't cause the mass of the nucleus to change Can it be predicted when any one nucleus will decay - ANSWER: No but the half-life is a constant that enables the activity of a very large number of nuclei to be predicted during the decay Contamination lasts for a _______ time and the source of the radiation is _______ to an object - ANSWER: .Long .Transferred Define current - ANSWER: The flow of electrical charge Define irradiation and give an example - ANSWER: Exposing an object to nuclear radiation, but doesn't make it radioactive e.g. radioactive dust emitting beta radiation, which "irradiates" your skin Define isotope - ANSWER: Atoms with the same number of protons but different number of neutrons Define non-renewable energy resource - ANSWER: Used more for large-scale energy supplies due to the large energy output per kilogram of fuel (renewable resources cannot provide such a large amount of energy as easily) Define power - ANSWER: The rate at which energy is transferred or the rate at which work is done Define radioactive contamination and give an example - ANSWER: Unwanted presence of radioactive atoms on other materials - the hazard is the decaying of the contaminated atoms releasing radiation e.g. radioactive dust settling on your skin (your skin becomes contaminated) Define renewable energy resource - ANSWER: Energy which can be replenished as it is used