Topic 10 + 11 - ELECTRICITY AND STATIC ELECTRICITY

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S K

Cards (69)

What is current?
Current is the flow of electrons around the circuit. Current only flows when there is a potential difference in the circuit (voltage) and the circuit is complete.
What is the formula of charge? 
charge = current * time
What is current also known as?
The rate of charge
Memorise this.
What is potential difference?
Potential difference (volts) is the driving force that pushes the charge around the circuit.
what is the other definition of potential difference?
The energy transferred per unit charged.
What is the formula for energy transferred? 
energy transferred = Charge moved * potential difference. (E = Q*V)
What is the unit for resistance? 
Ohms (Ω).
What is the formula for potential difference (voltage)?
potential difference = current * resistance.
What happens to the temperature when the resistance in a circuit increases?
The temperature increases as the electrons in the wires collide with the ions which causes them to vibrate - releasing energy.
Where must the ammeter be placed in a circuit?
In series with the circuit.
where must the voltmeter be placed in a circuit?
parallel with the component you are measuring the potential difference of.
What are the steps for the constructing circuits practical?
Setting up the Circuit:Create a loop for the circuit. Arrange the component and ammeter in any order. Place the voltmeter around the component.
Changing Power:Adjust power by changing the potential difference in the circuit.
Collecting Data:Measure how much electricity flows (current) for different power levels. Use both the ammeter and voltmeter.
Graph Time:Plot current and power on a graph. Use a formula to find resistance. See if the component behaves differently with changing power.
What is LURD? and what component does it correlate with?
Light intensity up, resistance down. LDRs.
What is TURD? and what component does it correlate with?
Temperature up, resistance down. Thermistors.
What is the function of a diode?
allows current to flow in one direction.
What is the correlation found between resistors and potential difference in I-V graphs?(when increasing current). 
Current is directly proportional to the potential difference.
What is the correlation found between Filament lamps and potential difference in I-V graphs? (when increasing current).
Increasing the current increases the temperature of the lamp - causing the resistance to increase. (It curves at the start and the end).
What is the correlation found between Diodes and potential difference in I-V graphs? (when increasing current). 
Current will only flow in one direction as there is very high resistance in the undesired direction.
What is a series circuit?
A circuit where the components are connected in a single path, allowing the flow of current through each component one after another.
what happens to a series circuit when a component is disconnected? 
The circuit breaks and stops working as there is only one path for the current to go through.
There's a bigger supply p.d. (voltage) when more cells are in series. E.g: 2 x 1.5V = 3V.
What happens to the current in a series circuit?
It stays the same. I1 = I2 = I3.
what happens to the voltage (P.D) in a series circuit? 
It is distributed evenly.
what happens to a series circuit the more you add resistors and why? 
The total resistance increases because the resistors have to share the Voltage given to them.
What is a parallel circuit?
A circuit with multiple paths for current to flow.
What happens if a component is disconnected in a parallel circuit?
The other components will continue to function normally as there are different pathways to power them.
What happens to the voltage (P.D) in a parallel circuit?
It stays the same across all components. V1 = V2 = V3.
What happens to the current in a parallel circuit?
The current is shared amongst each pathway with the current usually distributed unevenly. Total current = I1 + I2.
In a parallel circuit, the current either splits or rejoins.
What happens to the resistance in a parallel circuit?
The resistance decreases as you add more components parallel. As well as resistors. This is because of the current can go in more than one direction
energy transferred depends on current, voltage and time.
What is the formula for energy transferred?
E = I * V * t
what is the purpose of a fuse?
to prevent components from overheating due to high amounts of energy being transferred.
What is power in electricity?
Power is the energy that is transferred per second from an appliance.
What is the formula for power (watts)?
Power = Energy transferred / Time. $I*$ $V*$ $T/t$
What is the formula for electrical power?
Power = Voltage x Current. P = I*V or P = I^2 * R
What alternating current?
A type of current in which the charges are constantly changing direction. This means that the positive and negative ends of the voltage keeps on changing direction.
what is the main UK supply of electricity?
alternating current - 230V at 50Hz.
What is direct current?
The movement of charges in one direction.