Which one of the following metals is most commonly used for making filament of incandescent electric bulbs?

Tungsten is almost exclusively used for the filaments of incandescent electric bulbs due to its exceptional physical properties [1]. It possesses the highest melting point of all pure metals, approximately 3,410°C to 3,695 K, which allows it to be heated to incandescence without melting. Additionally, tungsten has a very low vapor pressure and a low rate of evaporation at high temperatures, which prevents the filament from thinning too rapidly and ensures a longer lifespan for the bulb [1]. While metals like copper and aluminium are excellent conductors, they are primarily used for electrical transmission lines because they lack the high-temperature resistance required for filaments [1]. Tungsten's high mechanical strength and resistance to oxidation in inert environments further solidify its role as the standard material for both traditional incandescent and halogen lamps [1].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > Activity 11.3 > p. 179