4.1: Charge and Current Flashcards
What is electric current?
The rate of flow of charge.
(Measured in amperes).
MAKE AN A3 EQUATIONS PAGE
Putting all equations here:
- charge, current and time
- I= Anev
What does ‘e’ represent and what are the units?
e is the elementary charge. E.g. a proton has charge +e, an electron has charge -e. The units are Coloumbs.
Give two examples of possible charge carriers.
- Electrons, in metals
- Ions, in electrolytes
What is conventional current?
Conventional current is the flow of positive charge.
Charge flows from the positive terminal of the battery to the negative terminal.
What is electron flow?
How do you connect an ammeter in a circuit?
An ammeter must be connected in series with the component.
What is Kirchhoff’s first law?
The sum of the current entering a junction is equal to the sum of the current leaving the junction.
CHARGE IS CONSERVED.
How do electrons drift?
(Hint: their velocity)
Electrons drift very slowly because they collide with ions in the, gradually move backwards and forwards towards the negative terminal when connected to a battery.
What is electromotive force?
The energy gained per unit charge by charges passing through and supply. Chemical energy is transferred to another form of energy.
What is the content of free conduction electrons in metals?
Metals contain a very large number of three conduction electrons.
What is the content of free conduction electrons in semiconductors?
Semiconductors contain a lower number of free conduction electron than metals.
What is the content of three conduction electrons in insulators?
Insulators contain very few (close to zero) free conduction electrons.
What is drift velocity?
The average velocity of an electron as it travels through a wire due to a potential difference.
