4.1 - Electricity - Charge and Current Flashcards
What is current defined as
Rate of flow of charge
What is the SI base unit for current
Amperes
What is 1 coulomb defined as
The amount charge in a time of 1 second when the current is 1 ampere
What is the elementary charge
1.6x10^-19
What is the equation for number of electrons
Q = Ne
What is current in metals carried by
electrons
What are liquids that can conduct a charge called
Electrolytes
What are electrolytes
Ionic solutions (contains both positive and negative ions)
What is conventional current
Rate of flow of charge from the positive to the negative terminal
In metals what is electron flow
Where the flow is in the opposite direction to conventional current (from negative to positive terminal)
What is Kirchhoff’s first law
The total current entering a junction or a node is equal to the charge leaving the node as no charge is lost. (conservation of charge)
Can charge be created or destroyed
No
What is the mean drift velocity equation ?
I = nAve / current = cross sectional area X number of electrons X drift velocity X electron charge
What is the charge of a proton
1.6x10^-19
What is the charge of an electron
-1.6x10^-19
What is mean drift velocity defined as
The average velocity of the electrons as they travel down the wire ,colliding with positive metal ions
Do conductors have a high or low number density of free electrons per unit volume
They usually have very high number densities
What carries charge in electrolytes
Ions
Order conductors, semiconductors and insulators in order from highest ‘n’
Conductors
Semiconductors
Insulators
