Fuse class 10 | 10th class physics | safe use of electricity | punjab, federal, kpk, balochistan скачать в хорошем качестве

Fuse class 10 | 10th class physics | safe use of electricity | punjab, federal, kpk, balochistan

Fuse 10th class physics chapter 14 | 10th physics chapter 14 safe use of electricity | urdu / hindi 14.14 SAFE USE OF ELECTRICITY IN HOMES In order to protect persons, devices and property from the hazards of electricity there is a need of extensive safety measures in household electricity. Take much care to use fuses and circuit breakers in an electric circuit as safety devices. They prevent circuit overloads that can occur when too many appliances are turned ON at the same time or when a short circuit occurs in one appliance. Fuse A fuse is a safety device that is connected in series with the livewire in the circuit to protect the equipments when excess current flows. It is short and thin piece of metal wire that melts when large current passes through it. If a large, unsafe current passes through the circuit, the fuse melts and breaks the circuit before the wires become very hot and cause fire. Fuses are normally rated as 5 A, 10 A, 13 A,30 A, etc. Different types of fuses are shown in Fig.14.18. Following safety measures should be taken while using fuses in household electrical circuits: (i) Fuses to be used should have slightly more rating than the current which the electrical appliance will draw under normal conditions. For example, for a lightning circuit choose a 5 A fuse as the current drawn by each lamp is very small (about 0.4 A for a 100 W lamp). In such circuit, 10 lamps of 100 W can be safely used as the total current drawn is only 4 A which can be calculated using the formula P = VI. Fig. 14 .18: Different types of fuses Identifying Circuit Components CURRENT ELECTRICITy (ii) Fuses should be connected in the livewire so that the appliance will not operate after the fuse has blown. (iii) Switch OFF the main before changing any fuse. Circuit Breaker The circuit breaker (Fig. 14.19) acts as a safety device in the same way as a fuse. It disconnects the supply automatically if current exceeds the normal value. When the normal current passes through the livewire the electromagnet is not strong enough to separate the contacts. If something goes wrong with the appliance and large current flows through the livewire, the electromagnet will attract the iron strip to separate the contacts and break the circuit (Fig. 14.20). The spring then keeps the contacts apart. After the fault is repaired, the contacts can then be pushed back together by pressing a button on the outside of the circuit breaker box. Earthwire Sometimes, even the fuse cannot capture the high currents coming from the livewire into the household appliance. Earthing further protects the user from electric shock by connecting the metal casing of the appliance to Earth (a wired connection to the bare ground). Many electrical appliances have metal cases, including cookers, washing machines and refrigerators. The Earthwire provides a safe route for the current to flow through, if the livewire touches the casing (Fig.14.21). We will get an electric shock if the livewire inside an appliance comes loose and touches the metal casing. Dear students you have heard some terns like fuse in hindi, fuse in urdu, fuse 10th physics, 10 class physics fuse and 10th physics chapter 14 safe use of electricity. Related searches 1. 10th class physics chapter 14 fuse 2. 10th class physics chapter 14 safe use of electricity 3.