Electricity powers everything from your phone to your PlayStation, and... Show more
Physics86 views·Updated May 21, 2026·2 pagesElectricity Knowledge Organizer - Physics Topic 2 Complete Guide
Annie@annie.park
1
of 2
Basic Electrical Concepts and Circuits
Think of current as the flow of electrical charge - it's like water flowing through pipes, measured in amps (A). For current to flow, you need a complete circuit and a driving force called potential difference or voltage, measured in volts (V). This voltage pushes the charge around the circuit.
Resistance acts like a narrow pipe that slows down the flow, measured in ohms (Ω). The relationship between these three is dead simple: V = I × R (voltage equals current times resistance). You'll use this formula constantly in your calculations.
Different components behave differently in circuits. Filament lamps get hot and their resistance increases with temperature. Ohmic conductors have constant resistance, whilst diodes only let current flow in one direction. LDRs (light dependent resistors) have low resistance in bright light, and thermistors have low resistance when hot.
Quick Tip: Remember that charge (Q) = current (I) × time (t), where charge is measured in coulombs. This helps you calculate how much electrical charge flows in a given time.
In series circuits, components share the voltage but have the same current throughout. In contrast, the resistance of all components adds up, making the total resistance higher.
2
of 2
Power, The National Grid, and Electrical Safety
Power tells you how quickly energy is transferred, and you've got two key formulas: P = VI (power equals voltage times current) and P = I²R. These help you work out how much electrical energy appliances use, which is measured using E = Pt (energy equals power times time).
The National Grid is brilliant engineering - it's the massive system of cables and transformers covering the UK. It uses high voltage and low current to transfer electricity efficiently from power stations to your home. Step-up transformers increase voltage whilst decreasing current, and step-down transformers do the opposite.
Static electricity happens when you rub insulating materials together, causing electrons to jump from one object to another. This creates positive and negative charges that either attract (opposite charges) or repel (same charges). Too much static can cause dangerous sparks.
Safety Alert: The live wire (brown) carries 230V and can kill you if touched. Always remember that your body is at 0V, so touching the live wire creates a massive potential difference through you.
Household electricity uses alternating current (a.c.) at 230V and 50Hz frequency, meaning the current constantly changes direction. This is different from direct current (d.c.) from batteries, which always flows in the same direction. Parallel circuits are brilliant because each component works independently - if one breaks, the others keep working.
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Physics86 views·Updated May 21, 2026·2 pagesElectricity Knowledge Organizer - Physics Topic 2 Complete Guide
Annie@annie.park
Electricity powers everything from your phone to your PlayStation, and understanding how it works is absolutely essential for GCSE physics. Let's break down the key concepts that'll help you ace your exams and understand the electrical world around you.
1
of 2Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Basic Electrical Concepts and Circuits
Think of current as the flow of electrical charge - it's like water flowing through pipes, measured in amps (A). For current to flow, you need a complete circuit and a driving force called potential difference or voltage, measured in volts (V). This voltage pushes the charge around the circuit.
Resistance acts like a narrow pipe that slows down the flow, measured in ohms (Ω). The relationship between these three is dead simple: V = I × R (voltage equals current times resistance). You'll use this formula constantly in your calculations.
Different components behave differently in circuits. Filament lamps get hot and their resistance increases with temperature. Ohmic conductors have constant resistance, whilst diodes only let current flow in one direction. LDRs (light dependent resistors) have low resistance in bright light, and thermistors have low resistance when hot.
Quick Tip: Remember that charge (Q) = current (I) × time (t), where charge is measured in coulombs. This helps you calculate how much electrical charge flows in a given time.
In series circuits, components share the voltage but have the same current throughout. In contrast, the resistance of all components adds up, making the total resistance higher.
2
of 2Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Power, The National Grid, and Electrical Safety
Power tells you how quickly energy is transferred, and you've got two key formulas: P = VI (power equals voltage times current) and P = I²R. These help you work out how much electrical energy appliances use, which is measured using E = Pt (energy equals power times time).
The National Grid is brilliant engineering - it's the massive system of cables and transformers covering the UK. It uses high voltage and low current to transfer electricity efficiently from power stations to your home. Step-up transformers increase voltage whilst decreasing current, and step-down transformers do the opposite.
Static electricity happens when you rub insulating materials together, causing electrons to jump from one object to another. This creates positive and negative charges that either attract (opposite charges) or repel (same charges). Too much static can cause dangerous sparks.
Safety Alert: The live wire (brown) carries 230V and can kill you if touched. Always remember that your body is at 0V, so touching the live wire creates a massive potential difference through you.
Household electricity uses alternating current (a.c.) at 230V and 50Hz frequency, meaning the current constantly changes direction. This is different from direct current (d.c.) from batteries, which always flows in the same direction. Parallel circuits are brilliant because each component works independently - if one breaks, the others keep working.
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What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
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