Statistics for AQA - A Level Physics - Electricity #2

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Hint	Answer	% Correct
Describe a Metallic Conductor	A material containing delocalised electrons that can carry electrical current	0%
Describe an electrical conductor	A material containing free charge carriers	0%
Describe a Semiconductor	A material where the number of free charge carriers varies (e.g. with temperature)	0%
Define a superconductor	A material with a resistivity of zero below a critical temperature	0%
Describe an electrical insulator	A material with no free electrons/charge carriers	0%
Define Resistivity	A measure of a material's opposition to current (=RA/L)	0%
What is meant by a charge carrier	A particle that can move in a material and transfer energy (e.g. electrons in metals, ions)	0%
Why does current lead to heating in resistors	Electrons collide with the lattice ions and transfer some of their kinetic energy to the ion's vibrations.	0%
Why does resistance increase with temperature	Lattice ion vibrations increase causing more frequent collisions between electrons and lattice ions.	0%
What are the units of resistivity	Ωm	0%
Give a use of a superconductor	MRI scanners, particle accelerators, maglev trains.	0%
Equation for resistivity	rho = RA / L	0%
What is meant by the critical temperature?	The temperature below which a material becomes a superconductor.	0%