Charge and current Flashcards
Define electric current
The rate of flow of charge.
What is one ampere?
One coulomb of charge passing through a given point per second
How do you find the net charge?
Q=+/-ne
N is the number of electrons
What does it mean when charge is quantised?
Charge can only take certain values- multiple of e
What experiment was used to determine the amount of charge on an electron?
The oil drop experiment
What are charge carriers in metals?
Electrons
What are charge carriers in liquids?
Ions
What is the structure of a metal?
A lattice of positive ion surrounded by delocalised electrons.
Positive ions aren’t free move they only vibrate around a fixed point.
How do you produce a higher current?
- Add more electrons to pass a given point per second
2.Make the same number of electrons pass but at a faster rate.
What is conventional current?
Current is the positive ions moving from the positive terminal toward the negative.
What is the direction of electron flow?
It is always opposite the conventional currents- negative terminal to positive terminal.
What are liquids that carry electrical current called?
Electrolytes
What is the ideal ammeter?
Zero resistance so it has no affect on the current
State the conservation of charge
Charge can neither be created or destroyed only transferred.
What is Kirchhoff’s first law?
The sum of currents into a junction is equal to the sum of currents leaving the junctions.
