Explain what the resistivity equation of a material is transcribing | Resistance per unit length and unit cross-sectional area at a specified temperature of a material |
Describe how a thermosistor can be used as a temperature sensor | The resistance decreases as the temperature increases, so at low temperatures, the resistance of a thermistor is high and little current can flow through them but at high temperatures the resistance is low and so current flows which could activate possibly an alarm |
Why would you use a superconductor for the creation of a magnetic field | Currently magnetic fields are created using a constant power source
All superconductors create a magnetic field so the power source as a whole would not be necassary
This saves money and the enviroment because fossil fuels are the main power source of the world |
What happens to the resistance if you increase the diameter of a wire?
And explain why? (without the equation) | Decreases
Area being greater means theres more electrons being able to flow |
What is the equation of resistivity in words | (electrical resistance X cross-sectional area) / length of the material |
What is the effect of temperature on resistance of metal conductors | The resistance linearly increases as the temperature of a metallic conductor increase |
What is the effect of temperature on resistance of metal thermosistors | Their resistance decreases with an increase in temperature |
What is the relationship between current and resistance | Resistance is inversely proportional to the current |
What is superconductivity | A property of certain metals that have zero resistivity at/ below a critical temperature |
Why would you assume that the superconductivity critical temperature of mercury and aluminum would be differnt? | Because differnt superconducting metals have different temperatures that they achieve superconductivity |
What are some applications of superconductors | Production of super strong magnetic fields
Reduction of energy lost in transmission of electrical power |
Why would you use a superconductor for reducing energy loss in transmission of energy | Because resistance causes heat which is a loss of useful energy for energy transmission. So in using a superconductor the resistance is removed and so the heat and wasted energy is obsolete as well |
Why when the temperature of a metal conductor is increased does its resistance increase | Temperature increase increases the kinetic energy of the atoms (how much and fast they move)
This means the electrons collide with more atoms more frequently, slowing them down
So current decreases and resistance increases |