2.2 resistance Flashcards
(24 cards)
What is Potential Difference?
Energy supplied per unit charge, measured in volts.
What is Resistance?
Measure of difficulty for current to flow, in ohms.
What is Ohm’s Law?
Current is proportional to potential difference across a conductor.
What is Resistivity?
Material’s property affecting current flow, measured in ohm-metres.
What is an I-V Characteristic?
Graph showing current variation with potential difference.
What is the Filament of a Lamp?
Curved I-V graph due to increasing resistance with temperature.
What happens in a Metal Wire at Constant Temperature?
Current directly proportional to potential difference, constant resistance.
What is Power?
Energy transferred per unit time, calculated as P=IV.
What is Superconductivity?
Material conducts with zero resistance below transition temperature.
What is Transition Temperature?
Temperature below which a material becomes superconductive.
What are High Temperature Superconductors?
Materials with transition temperatures above 77K.
What are Electromagnets?
Devices using electric current to generate magnetic fields.
What are MRI Scanners?
Use superconducting magnets for strong magnetic fields.
What is a Radiofrequency Pulse?
Electromagnetic signal altering proton alignment in MRI.
What are Particle Accelerators?
Devices using magnets to change paths of subatomic particles.
What is Current?
Flow of electric charge, measured in amperes (A).
What is Voltage?
Electric potential difference, driving current flow.
What is an Ohm?
Unit of resistance, equivalent to volts per ampere.
What happens during Collisions in Conductors?
Free electrons collide with ions, causing resistance.
What is the Temperature Effect on Resistance?
Resistance increases with temperature in conductors.
What is Energy Transfer?
Process of energy moving from one system to another.
What are Conductors?
Materials that allow easy flow of electric current.
What are Non-ohmic Conductors?
Materials that do not obey Ohm’s Law.
What are Ohmic Conductors?
Materials that maintain constant resistance under varying current.
