Correct Option
The correct option is (c).
Explanation
The operation of electrical appliances such as bulbs, irons, and geysers is based on the heating effect of electric current (Joule heating). When current flows through a conductor with high resistance, electrical energy is converted into heat energy according to the formula \( H = I^2Rt \).
Statement-wise Analysis
- Statement 1 is Incorrect.
In technical terminology, a filament is a very thin wire, typically made of Tungsten, used primarily in incandescent light bulbs. Its primary function is to get heated to such a high temperature that it emits light (glows). An electric geyser, however, uses a heating element (usually a thicker coil made of Nichrome) designed specifically to generate heat to warm water, not to emit light.
- Statement 2 is Correct.
A heating element is the core component found in thermal appliances like electric irons, toasters, and room heaters. These elements are made of alloys like Nichrome (nickel and chromium) which have high resistivity and high melting points, allowing them to generate significant heat without oxidizing or melting at high temperatures.
- Statement 3 is Correct.
Both the filament in a light bulb and the heating element in an iron or geyser operate on the same principle: the heating effect of electric current. In a filament, the heat generated is sufficient to produce visible light, whereas, in a heating element, the heat is utilized for thermal applications.
Key Takeaway: While both filaments and heating elements utilize Joule heating, a filament is designed for light emission (e.g., bulbs), whereas a heating element is designed for heat generation (e.g., geysers, irons).