P4 - Eletrical Circuits Flashcards
If an atom loses an electron, what charge does it become?
Positively charged
If an atom gains an electron, what charge does it become?
Negatively charged
What is charging by friction?
Rubbing objects together so they share their electrons and gain charges
Do opposite charges attract or repel?
Attract
Do similar charges attract or repel?
Repel
What do all charged objects have around them?
An electrical field
Do objects placed inside an electrical field experience a bigger force when they are close or far away from the object emitting the field?
They experience a bigger force when they are closer to the object emitting the field
What is a cell and how is its symbol drawn?
The cell provides the ‘push’ for electrons in a circuit
It is draw with a longer line on the left and a shorter line on the right
What is an ammeter and how is its symbol drawn?
An ammeter is used to measure current
It is drawn with an A inside a circle
What is a voltmeter and how is its symbol drawn?
A voltmeter measures the potential difference (voltage)
It is drawn with a V inside a circle
What is a bulb and how is its symbol drawn?
A bulb emits light when a current passes through it
It is drawn with an X inside a circle with the X touching the sides of the circle
What is a LDR and how is its symbol drawn?
An LDR is a light dependent resistor
It is drawn with a circle with a rectangle in it with two arrows pointing in the top left towards it
What is a fuse and how is its symbol drawn?
A fuse melts and breaks the circuit if the current gets too high
It is drawn with a rectangle with a line through it
What is a resistor and how is its symbol drawn?
A resistor limits the current in a circuit
It is drawn with a rectangle
What is a switch and how is its symbol drawn?
A switch enables current in a circuit to be switched on and off
It is drawn with two circles and a line between them, either closed or open
What is a variable resistor and how is its symbol drawn?
A variable resistor allows the current in a circuit to be varied
It is drawn with a rectangle and an arrow cutting through it from the bottom left to top right corner
What is electric current in a circuit?
Electric current is the flow of electrons in a circuit
What is electric current measured in?
Amps
What is potential difference?
The amount of energy transferred by each coulomb of electrons that passes between two points in the circuit
What is a resistance in a circuit?
Resistance is the opposition to the flow of electrons (current)
It describes everything that resists or opposes the flow of electrons
What is Ohm’s law?
The current through a resistor at constant temperature is directly proportional to the potential difference across the resistor
What is a series circuit?
A circuit containing only one loop where all the electrical components of a circuit are wired one after the other
What can you say about the current in a series circuit?
The current that flows across each component in a series circuit is always the same
What can you say about the potential difference in a series circuit?
The total potential difference is shared between all the components in the circuit
(It is not always equally shared)
What can you say about the resistance in a series circuit?
The total resistance in a series circuit is the sum of the resistance of each component in the circuit added up
What is a parallel circuit?
A circuit where components are connected in separate loops along different ‘branches’
What can you say about the current in a parallel circuit?
The total current in the circuit is the sum of the current in each separate branch added up
What can you say about the potential difference in a parallel circuit?
The potential difference across each component in the circuit is the same
What can you say about the resistance in a parallel circuit?
The total resistance of the parallel circuit is the sum of the inverse of the resistance of each component in the circuit
1/Rtotal = 1/R1 + 1/R2 + 1/R3 …
What is current?
A measure of the flow of electrons around a circuit
What is a battery?
2 or more cells put together
What is potential difference also known as?
Voltage
What is the voltage of a circuit?
The force driving the flow of electrons in a circuit
What is resistance measured in?
Ohms
Which way does current flow in a circuit?
From the positive terminal to the negative terminal
