9.1-9.11 Energy Power Resistance Quizlet Cards Flashcards
What is potential difference?
The work done per unit charge between two points
What is the SI unit for potential difference?
Volt (V)
What units are equivalent to the volt?
Joules per Coulomb (JC⁻¹ )
What is EMF (Electromotive force)?
The work done per unit charge supplied to the charge carriers
How is a voltmeter connected?
In parallel.
What is the resistance of an ideal voltmeter?
Infinite.
What is thermionic emission?
The emission of electrons from the surface of a heated metal.
What is the work done on an electron when it passes through a p.d. of V volts?
eV where e is the charge on the electron.
What is Ohm’s Law?
For a metallic conductor at constant temperature the p.d. is proportional to current.
What is electrical resistance?
The opposition of an object to a flow of current through it.
How is resistance calculated?
V/I
What units are equivalent to an Ohm?
VA⁻¹
Why does resistance increases with temperature?
The amplitude of lattice ion vibrations increases causing more frequent collisions between electrons and lattice ions, leading to the electrons doing more work as they move through the wire.
Why does current flow lead to heating in components?
Electrons collide with the lattice ions and transfer some of their kinetic energy to the lattice ion’s vibrations.
What is an Ohmic conductor?
An object for which p.d. is proportional to current.
