NCERT Solution for Class 10 Science Chapter 13
Magnetic Effects of Electric Current
NCERT Books for Session 2022-2023
CBSE Board and UP Board
Exercises Questions
Page No-241
Questions No-18
What is the function of an earth wire? Why is it necessary to earth metallic appliances?
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The earth wire, or grounding wire, serves as a safety measure in electrical systems. Its primary function is to provide a path of least resistance for electric current to flow into the ground in the event of a fault.
When metallic appliances are grounded, the earth wire helps to prevent electric shock and reduces the risk of fire. If there’s a fault, such as a short circuit, and the live wire comes into contact with the metal casing of an appliance, the earth wire provides a low-resistance path for the current to flow into the ground. This causes a protective device, like a circuit breaker, to trip and disconnect the power, preventing potential harm.
In essence, grounding ensures that any stray current has a safe route to disperse, reducing the risk of electrical accidents. It’s like giving electricity a safe escape route, preventing it from taking unexpected and potentially dangerous detours through appliances or, worse, through you!
The earth wire functions as a safety measure, specially for those appliances that have a metallic body e.g., electric press, toaster, table fan, refrigerator, room cooler etc. The metallic body of the appliance is connected to the earth wire, which provides a low resistance conducting path for electric current. It ensures that any leakage of current to the metallic body of an appliance keeps its potential same as of earth. As a result, the user would not get a severe electric shock, even if he touches the body of appliance.
The earth wire transfers any leakage of electric current to the earth. The leaked current can otherwise reach the metallic body of an appliance and can lead to electric shock. Earth wire prevents from electric shock by safety transferring the leaked current to the earth.
Earth wire is a safety measure that prevents short circuits and shock. When a live wire touches the metallic case of an electric gadget, the electric current flows from the casing of the appliance to the earth through the copper wire. As the earth offers very low or almost no resistance to the flow of current, so large current passes through the copper wire instead of the human body. Due to this large current heat is produced in the circuit and hence the fuse in the circuit melts. So, the circuit is switched off automatically and the electric appliance is saved from burning and no electric shock to the human body.
The metallic body of electric appliances is connected to the earth by means of earth wire so that any leakage of electric current is transferred to the ground. This prevents any electric shock to the user. That is why earthing of the electrical appliances is necessary.
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