Electric Quantities Flashcards
What is current
Rate of flow of charge
What is the formula for current
I=q/t
What is the definition of one amp
When one coulomb of charge flows through a conductor/wire every second
What is voltage
The amount of energy supplied per coulomb of charge
What is the formula of voltage
V=IR, V=E/Q, E=VIT
What is conventional current
The flow of current from positive to negative.
The flow of free electrons from negative to positive
What is emf
The amount of energy supplied to each coulomb of charge from non electrical to electrical form to move the charges around the circuit
What is pd
The amount of energy supplied to each coulomb of charge from electrical to non electrical form between two points in a circuit
What is an ammeter
It’s used to measure current in a circuit and is always connected in series and has negligible resistance
What is a voltmeter
It’s used to measure voltage across a component and is always connected in parallel and has infinite resistance
What is a short circuit
A short circuit occurs when there’s a path with less resistance as current travels through the shortest path
What is resistance
The ratio of the voltage across the component to current flowing through the component
What is the definition of one ohm
Resistance of the material when one amp of current flows through it if the pd applied across is one volt
What is ohms law
Current flowing through a conductor is directly proportional to the pd across it provided that resistance is constant
What is resistivity
The property of a material that determines it’s ability to conduct electricity
What is the relationship between resistance and length
They are directly proportional
What is the relationship between resistance and cross sectional area
They are inversely proportional
Current in series circuits
Current is equal at all points
Current in parallel circuits
Current is shared by each branch
Voltage in series circuits
Voltage is split
Voltage in parallel circuits
Voltage is equal in every branch
What is Direct current(DC)
Flow of electrons in one direction only
What is AC
Direction of flow reverses periodically
What are electric insulators
Materials that don’t have free electrons therefore electricity doesn’t flow through them
What are electric conductors
Materials that have free electrons and electricity flows through them
How can an insulator become charged
By rubbing with another insulator due to which electrons are transferred from one material to the other
What is confined charge
When electrons are transferred in a certain region and cant flow because the object is an insulator
What is induced charge
The process by which electrical charges in an electrically neutral object are re arranged due to a presence of a charged object close to them without any contact
What is earthing
The process by which a conductor can be neutralised electrically either by adding or removing electrons from the conductor. Earthing is done by connecting the conductor to the ground
What is an electric field
A region of space around a charged object in which it can exert a force on another charged object.
What direction do positive charges go
Outwards
What direction do negative fields go
Inwards
What are the dangers of static electricity
Filling fuels, rolling paper and grain shoots
What are the dangers of static electricity
Filling fuels, rolling paper and grain shoots
