| An electric cable typically contains three wires: live, neutral, and earth. | Electric Cable Composition |
| What are the three wires commonly found in an electric cable? | Live wire, neutral wire, and earth wire. |
| Electric wires are colour-coded for easy identification. In the UK, the live wire is brown, the neutral wire is blue, and the earth wire is green and yellow. | Colour Coding of Electric Wires |
| What is the colour coding for the live, neutral, and earth wires in the UK? | Brown for live, blue for neutral, and green/yellow for earth. |
| The brown live wire carries the alternating potential difference from the power supply. It has a potential difference of about 230 V. | Live Wire |
| What is the function and potential difference of the live wire? | The live wire carries the potential difference from the power supply and has a potential difference of about 230 V. |
| The blue neutral wire completes the circuit and has a potential difference of about 0 V. | Neutral Wire |
| What is the function and potential difference of the neutral wire? | The neutral wire completes the circuit and has a potential difference of about 0 V. |
| The green and yellow earth wire is a safety wire that prevents the appliance's case from becoming charged. It is usually at 0 V and provides a path for current only in case of a fault. | Earth Wire |
| What is the function and potential difference of the earth wire? | The earth wire prevents the case from becoming charged, usually at 0 V, and provides a path for current in case of a fault. |
| The earth wire ensures safety by preventing the appliance's case from becoming charged, reducing the risk of electric shock. | Safety Function of Earth Wire |
| What safety function does the earth wire serve? | The earth wire prevents the appliance's case from becoming charged, enhancing safety. |
| The live wire is dangerous, and touching it can result in an electric shock. | Live Wire Danger |
| Why is the live wire considered dangerous? | Touching the live wire can lead to an electric shock. |
| An electric shock can have severe consequences, including injury or death. | Electric Shock Consequences |
| What are the potential consequences of an electric shock? | Injury or death. |
| When a person touches a live wire, their body links the mains supply (230 V) and the earth (0 V). | Body as a Conductor |
| What happens when a person touches a live wire? | The person's body links the mains supply (230 V) and the earth (0 V). |
| The potential difference between the live wire and earth causes electric current to flow through the person's body. | Potential Difference and Electric Current Flow |
| What causes electric current to flow through the body when touching a live wire? | The potential difference between the live wire and earth. |
| The electric shock from touching a live wire can be lethal, and it may result in death. | Lethal Electric Shock |
| How severe can an electric shock from a live wire be? | It can be lethal, potentially resulting in death. |
| Even when an appliance is switched off, there may still be a potential difference, and touching it can lead to an electric shock. | Electric Shock Risk When Appliance Is Switched Off |
| Can an electric shock occur when an appliance is switched off? | Yes, even when an appliance is switched off, there may still be a potential difference, posing a risk of electric shock. |
| The earth wire protects against electric shocks by providing a safe route for electric current to the ground. | Earth Wire Purpose |
| What is the primary purpose of the earth wire? | The earth wire protects against electric shocks by providing a safe route for electric current to the ground. |
| A loose live wire in a plug may touch the case of the appliance, creating a hazard. | Loose Live Wire Hazard |
| What hazard can occur if a live wire becomes loose and touches the case of an appliance? | It can create a hazard, potentially leading to electric shocks. |
| If the case of an appliance is made of metal and becomes charged, it poses a risk of electric shock. | Charged Metal Case |
| What risk does a charged metal case of an appliance pose? | It poses a risk of electric shock. |
| The earth wire is connected to the case of the appliance, providing a route to the ground. | Earth Wire Connection |
| How is the earth wire connected to the case of an appliance? | The earth wire is connected to the case, providing a route to the ground. |
| The earth wire allows the current to flow to the ground, bypassing a person. | Current Flow to Ground |
| What route does the current take when the earth wire is connected? | The current flows to the ground through the earth wire, bypassing a person. |
| Earth wires prevent electric shocks by providing a low-resistance path for the current. | Earth Wire Preventing Electric Shocks |
| How do earth wires contribute to preventing electric shocks? | They provide a low-resistance path for the current, diverting it away from people. |
| A fuse is a safety device that breaks a circuit if too much current flows through it, preventing devices from drawing excessive current and overheating. | Fuse Function |
| What is the primary function of a fuse? | A fuse breaks a circuit if too much current flows through it, preventing devices from drawing excessive current and overheating. |
| A fuse contains a thin wire inside a protective tube. | Fuse Components |
| What are the components of a fuse? | A fuse contains a thin wire inside a protective tube. |
| When current flows through the fuse, the thin wire heats up. If too much current flows, the wire melts, breaking the circuit. | Fuse Operation |
| How does a fuse operate when too much current flows through it? | The thin wire inside the fuse heats up, and if the current is excessive, the wire melts, breaking the circuit. |
| If the thin wire in a fuse melts, it breaks the circuit, preventing further current flow. | Circuit Breakage |
| What happens if the thin wire in a fuse melts? | It breaks the circuit, preventing further current flow. |
| Fuses prevent devices from drawing too much current and overheating by breaking the circuit. | Overheating Prevention |
| How do fuses contribute to preventing devices from overheating? | They break the circuit if too much current flows, preventing overheating. |
| Fuses can melt if there's a fault and a high current flows through the earth wire. | Fault Protection |
| Under what circumstances can fuses melt to provide fault protection? | Fuses can melt if there's a fault and a high current flows through the earth wire. |
| Fuses in plugs are connected to the live wire. | Live Wire Connection |
| Which wire are fuses in plugs connected to? | Fuses in plugs are connected to the live wire. |
| Different devices require fuses with varying current ratings to match their normal operating current. | Fuse Selection |
| Why do different devices need fuses with different current ratings? | Different devices draw different amounts of current, so they need fuses with ratings matching their normal operating current. |
| A fuse should be chosen with a rating slightly higher than the current the device usually uses. | Appropriate Fuse Rating |
| What consideration should be given when selecting a fuse for a device? | A fuse should be chosen with a rating slightly higher than the current the device usually uses. |
| Circuit breakers automatically switch off the power when there's an unexpected change in the current to protect against electrical faults. | Circuit Breaker Function |
| What is the primary function of a circuit breaker? | Circuit breakers automatically switch off the power when there's an unexpected change in the current to protect against electrical faults. |
| Circuit breakers detect changes in the current. | Current Change Detection |
| What do circuit breakers detect in the electrical system? | Circuit breakers detect changes in the current. |
| Circuit breakers automatically switch off the power in response to unexpected changes in the current. | Automatic Power Switching |
| How do circuit breakers respond to unexpected changes in the current? | They automatically switch off the power. |
| Circuit breakers are much faster than fuses in responding to changes in the current. | Speed Comparison with Fuses |
| In comparison to fuses, how fast are circuit breakers in responding to changes in the current? | Circuit breakers are much faster than fuses. |
| Circuit breakers have a switch that allows them to be reset after they cut off the current. | Resettable |
| What feature do circuit breakers have that allows them to be reused after cutting off the current? | Circuit breakers have a switch that allows them to be reset. |
| Circuit breakers do not need to be replaced after they cut off the current. | Replacement Requirement |
| Unlike fuses, what is the advantage of circuit breakers in terms of replacement? | Circuit breakers do not need to be replaced after they cut off the current. |
| Circuit breakers have a switch that resets them, allowing for easy reuse. | Resettable |
| How can circuit breakers be reset after cutting off the current? | Circuit breakers have a switch that resets them. |
| Circuit breakers protect against electrical faults by switching off the power. | Electrical Fault Protection |
| What type of protection do circuit breakers provide against electrical faults? | Circuit breakers protect against electrical faults by switching off the power. |
| Circuit breakers contribute to electrical safety by rapidly responding to faults and allowing for easy resetting. | Safety Feature |
| How do circuit breakers contribute to electrical safety? | Circuit breakers contribute to electrical safety by rapidly responding to faults and allowing for easy resetting. |
