Physics Electricity Test Flashcards
Two basic types of circuit are?
Series and parallel
What is an electrical current
The movement of charge between the terminals of an energy source
What must there be for a current to flow in a circuit
A full conducting path
A source of electrical energy
What do electrical conductors do and electrical insulators don’t
Allow electricity to flow through them
What is electric current
The amount of charge transferred per unit of time (the rate of flow of charge)
What is currents mathematical equation
I=Q/T
What is potential difference
The amount of energy given to one coulomb of charge passing through a supply
What is the formula for potential difference
V=E/Q
What is charge measure with
An ammeter
What is potential difference measured with
A voltmeter
What affects resistance
Length of resistor
Thickness of resistor
Temperature of resistor
Material of resistor
What is ohms law
V=IR
What is potential difference directly to proportionate too
If at a constant temperature, potential difference is directly proportionate to the current flowing through it
What is resistance
The opposition to the flow of charge
What is resistance measured in
Ohms
In a parallel circuit the branch with the highest resistance will have
The lowest split of current
In a series circuit the component with the highest resistance will have the
Highest share of voltage
What is power
A measure of energy transferred each second in a circuit. Measured in watts
What is the formula for power
P=E/T
What is the formula of power when
- Current and potential difference are known
- When current and resistance are known
- When potential difference and resistance are known
- P=IV
- P=IsquaredR
- P=vsquared/R
What is a direct current (d.c.)
A current which flows in only one direction
What is an alternating current (a.c.)
A current which flows in two direction and changes throughout its journey.
What is the main electricity voltage in the UK
230 volts
What is a potential divider
Two components connected in series, usually resistors
What is the equation to find a voltage of one of the resistors
V=(R1/R1+R2) x supply voltage
What is an LDR
A light dependant resistor which as the light lèvera increases the resistance decreases
What is a thermistor
A thermistor is a component which depends on temperature as when the temperature increases the resistance decreases.
What is a protection resistor
It is a resistor set in place specifically to stop a component from overheating or being overworked
What is a transistor
It is a circuit used as an electronic switch. It switches on at a certain voltage depending on if it is a mosfet or NPN
When does
- An NPN switch on
- A mosfet switch on
- 0.7 volts
2. 2 volts
