18. Heating effect in electrical appliances

There are many applications of the heating effect. Some of them are discussed in detail below.

We use many electrical appliances in our daily life. The heating effect of current is used in an electric iron to press our clothes, room heater to get rid of cold, electrical lamps to lit our rooms, etc. 

 

 

In all the electrical appliances, a coil of wire called an element is present. When these appliances are switched on, electric current flows through the circuit. This makes the element in the appliances to give out heat.
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Element in an appliance
 
Properties of the element:
The heating capacity of an element depends on three factors. They are,

These properties can vary depending on the requirements of heat.

 

Nichrome, an alloy of nickel and chromium, is used as a heating element in the electrical appliances. Nichrome is preferred as a heating element because

  

The heating coil of an electric heater is made of nichrome wire. A spiral coil of nichrome wire is put in a groove inside porcelain or any insulator frame. An insulator is used as it does not gets heated up. Due to the high resistance, the wire becomes red hot when current is passed through it. Thus, the heat produced by nichrome is utilised for cooking or heating.

 

 

The high-resistance nichrome wire coil is enclosed in mica sheets and is set in a massive metal block. Mica is a good conductor of heat but a poor conductor of electricity. Hence, the heating coil is implanted between mica sheets. The coil is powered by electricity to transfer heat to a metal block that is used to iron garments.