Flip Cards – Grade 9 Academic Science Question 1 The unit of measurement of resistance in an electrical circuit Flip Cards – Grade 9 Academic Science Answer 1 Ohms Resistance is measured in units of ohms The symbol is Ω Flip Cards – Grade 9 Academic Science Question 2 Two neutral materials are rubbed together to produce a static electrical charge by transferring or moving electrons from one of the materials to the other material. Flip Cards – Grade 9 Academic Science Answer 2 Charging by Contact According to the Triboelectric Series, some materials tend to readily take electrons while other materials give electrons. If electrons are taken, the material has a negative imbalance (i.e., more negative electrons than positive protons) and the material becomes negatively charged. Flip Cards – Grade 9 Academic Science Question 3 The formula for determining Percentage Energy Efficiency In a question, “What is the Percent Efficiency of an electrical fan is it uses 500 J of energy to produce 10 J of usable energy to turn the fan blades?” Flip Cards – Grade 9 Academic Science Answer 3 % Efficiency = Energy Out / Energy In X 100 If the fan uses 500 J of energy, the term “uses” means the fan took that energy IN If the fan produces 10 J of energy, the term “produces” implies that it is the energy given off or OUT Thus, % Efficiency = 10 / 500 X 100 Flip Cards – Grade 9 Academic Science Question 4 An imbalance of electric charge on the surface of a material Flip Cards – Grade 9 Academic Science Answer 4 Static Electricity Flip Cards – Grade 9 Academic Science Question 5 Charging a neutral object by contact with a charged object Flip Cards – Grade 9 Academic Science Answer 5 Charging by Conduction Flip Cards – Grade 9 Academic Science Question 6 A material that lets electrons move through it easily Flip Cards – Grade 9 Academic Science Answer 6 Conductor Flip Cards – Grade 9 Academic Science Question 7 The energy provided by the flow of electrons in an electric circuit Flip Cards – Grade 9 Academic Science Answer 7 Electrical Energy Flip Cards – Grade 9 Academic Science Question 8 Like charges repel AND opposite charges attract Flip Cards – Grade 9 Academic Science Answer 8 Law of Electric Charges Flip Cards – Grade 9 Academic Science Question 9 Charging a neutral object by bringing another charged object close to but not touching the neutral object Flip Cards – Grade 9 Academic Science Answer 9 Charging by Induction Flip Cards – Grade 9 Academic Science Question 10 A material that does not easily allow the movement or passage of electrons through it Flip Cards – Grade 9 Academic Science Answer 10 Insulator Flip Cards – Grade 9 Academic Science Question 11 A circuit in which the loads are connected end-to-end so that there is only one path for electrons to flow Flip Cards – Grade 9 Academic Science Answer 11 Series Circuit In a series circuit when one load is removed (e.g., light stops working), all loads stop working. Flip Cards – Grade 9 Academic Science Question 12 Natural energy resource that is unlimited (e.g., solar energy, wind energy) or can be replenished by natural processes in a relatively short period of time. Flip Cards – Grade 9 Academic Science Answer 12 Renewable Resource Flip Cards – Grade 9 Academic Science Question 13 A device used to measure electrical current Flip Cards – Grade 9 Academic Science Answer 13 Ammeter An ammeter is wired directly into the circuit as a series circuit. It measures the current flowing through a load. Flip Cards – Grade 9 Academic Science Question 14 The difference in electric potential energy per unit charge measured at two different points and measured in volts (V) Flip Cards – Grade 9 Academic Science Answer 14 Potential Difference or Voltage Flip Cards – Grade 9 Academic Science Question 15 The transfer of electrons between two neutral objects (made of different materials) that occurs when they are rubbed together or come into contact Flip Cards – Grade 9 Academic Science Answer 15 Charging by Friction Flip Cards – Grade 9 Academic Science Question 16 The rate at which electrical energy is produced or used Flip Cards – Grade 9 Academic Science Answer 16 Electrical Power Flip Cards – Grade 9 Academic Science Question 17 A circuit in which the loads are connected by branches so that there are two or more paths for electrons to flow. Flip Cards – Grade 9 Academic Science Answer 17 Parallel Circuit In a parallel circuit when one load is removed (e.g., light goes out), the other loads continue to work. Flip Cards – Grade 9 Academic Science Question 18 The measurement of units of electrical current Flip Cards – Grade 9 Academic Science Answer 18 Amps (A) Current (I) is measured as ampreses Flip Cards – Grade 9 Academic Science Question 19 A device that reduces the flow of electric current. Flip Cards – Grade 9 Academic Science Answer 19 Resistor A resistor could be a lamp, stove, computer, washing machine or electric can opener Flip Cards – Grade 9 Academic Science Question 20 I=V/R The relationship between voltage, current and resistance Flip Cards – Grade 9 Academic Science Answer 20 Ohm’s Law