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Heating element of iron made up of
Tungsten wire
Nichrome wire
Copper wire
Iron wire
Nichrome wire
The heating element of an electric iron is made of Nichrome wire, an alloy consisting primarily of nickel (approx 80%) and chromium (approx 20%). It is chosen for its high electrical resistivity and its ability to withstand high temperatures without oxidizing or melting.
The heating element of an electric iron is made of Nichrome wire, an alloy consisting primarily of nickel (approx 80%) and chromium (approx 20%). It is chosen for its high electrical resistivity and its ability to withstand high temperatures without oxidizing or melting.
H=I2Rt тАФ Heat produced in Joules where I is current (A), R is resistance (╬й), and t is time (s).
R=╧БALтАЛ тАФ Resistance formula relating resistivity (╧Б), length (L), and cross-sectional area (A).
The principle of operation is Joule Heating (or resistive heating). When an electric current I passes through a conductor with resistance R, electrical energy is converted into heat energy. The amount of heat generated is given by H=I2Rt. Nichrome's high resistivity ensures significant heat production even with a relatively short length of wire.
Nichrome has a high melting point of approximately 1400┬░C.
It forms a protective layer of chromium oxide on its surface, preventing further oxidation.
The high resistivity allows for compact heating element design.
Nichrome wire does not corrode easily at high temperatures.
High electrical resistance compared to pure metals.
Excellent resistance to oxidation and heat degradation.
Relatively expensive compared to iron or copper alloys.
Cannot be used for soldering as it does not wet easily.
Electric Irons
Toasters
Electric Kettles
Space Heaters
The melting point of Nichrome is significantly higher than that of copper (1085┬░C).
Tungsten is typically used in incandescent bulbs because it produces light at high temperatures, whereas Nichrome is optimized for steady heat dissipation.
B is correct тАФ Nichrome wire is used because it has high electrical resistivity and high resistance to oxidation at high temperatures.
In competitive exams, remember that materials like Tungsten have high melting points but are used for light emission, while Nichrome is specifically used for thermal energy conversion applications.