Electricity Topic Flashcards
Types of Transformers
Step-up transformer - increase voltage, decrease current
Step-down transformer - decrease voltage, increase current
Voltage Equation
Voltage (v) = Current (A) * Resistance (Ohms)
What is Static Electricity?
friction Vande Graaft generator
Insulators
Charge
What is Current Electricity?
Steady Current in closed circuit
Resistance Domestic Electricity
What is Electricity?
Flow of electrons through a wire or other component
What is Current?
Rate of flow of charge through a wire or another component
Measured using an ammeter
Measured in Amps (A)
Charge Equation
Charge = Current / Time
Q = I / T
What is Electrical Resistant
Measure of a components opposition to the flow of current
If the resistance of a variable has increased then the current decreases
If the resistance of a variable has decreased then the current increases
Ohms Law
If the Cell Voltage in a circuit is Constant, and if the Electrical Resistance Increases, the Electrical Current will Decrease
If the Electrical Resistance in a circuit is Constant, and if the Cell Voltage Increases, the Electrical Current will Increase
Potential Difference Equation
Potential Difference = Current / Resistance
V = I / R
What is Resistance?
When electrons flow through a wire (or any electrical component) they will experience Resistance - something that will Restrict their Movement/Make it difficult for them to get through
As the electron travels along, it will collide with atoms - Resistance
What is a Resistor?
Use to deliberately restrict the flow of electrons if needed
Resistance Equation
Resistance = Voltage / Current
R = V / I
What is a Series Circiut?
Voltage from a power supply is shared between components
What is a Parallel Circuit?
Every branch of the circuit receives the same voltage
What happens to the LDR resistance when the light intensity increases?
As the light intensity increases, the LDR resistance decreases.
This reduces the total resistance in the circuit, and increases the current.
The potential difference across the fixed resistor increases, so the potential difference across the LDR must decreases.
What happens to the resistance of the thermistor when the temperature increases or decreases?
As the temperature increases, the resistance of the thermistor decreases
As the temperature decreases, the resistance of the thermistor increases
Explain why the potential difference across the fixed resistor decreases as the temperature decreases
As the temperature decreases, the resistance of the thermistor increases. This means that the thermistor takes the greater share of potential difference, and the potential difference across the fixed resistor decreases.
What is non-contact force?
Objects that are charged can affect other charged objects, using the non-contact forces of static electricity
How does insulation gain charge by friction?
When insulating materials rub against each other, they may becomes charged. Electrons, which are negatively charged, may be ‘rubbed off’ one material onto the other.
- Material that gains electrons (negative charge)
- Material that loses electrons (positive charge)
What are electrical forces?
A charged object will experience non-contact force from another charged object. Type of force depends on charge.
Properties of attraction and repulsion are often used to show an object is charged
What are Electric Fields?
All charged objects have an electric field around them, shows how they will interact with other charged particles.
A Van de Graaff generator removes e- to produce + charge.
Static electricity is a non-contact force - this force will act on any charged positive in the electric field around the generator
What are Electric Field Shapes?
Electric field - region where charges experience a force
Fields are usually shown as a diagram with arrows:
- The direction of the arrows shows the way a positive charge will be pushed
What is the red wire and where does it come from?
Live wire - from the power station
What is the green and yellow wire and where does it come from?
Earth - safety wire
What is the blue wire and what does it do?
Neutral - to the power station
What is the fuse of a plug?
