Question

Tungsten is used in electric bulbs because:
(A) It is sonorous
(B) It is metallic
(C) It has high tensile strength.
(D) It has high density

Answer 1

Hint: Tungsten has the highest melting point and lowest vapour pressure among all the metals. At temperatures over${1650^0}C$, it has the highest tensile strength in the range of 1,00,000 – 5,00,000 psi at room temperature.

Complete step by step solution:
Tungsten has an atomic number – 74 and it belongs to group 6 of the periodic table. It is the heaviest member of its group. It is chemically abbreviated as W. The word tungsten itself means ‘heavy stone’. It is an important element used for everything from the household incandescent light bulb to radiation shielding. Some of its extraordinary properties are:
- It is solid at room temperature and possesses the highest melting point and lowest vapour pressure among all the metals.
- It also has the highest tensile strength known. This property of tungsten makes it readily available for incandescent and fluorescent light bulb filaments.
- Furthermore, due to its excellent corrosion resistance, it is highly resilient to acid attack by acids.
- Like all other metals, it is malleable and quite ductile. Even, it can be more easily pressed than other metals.
So, from the above properties of tungsten, only one is mentioned in the given options and that is, in option C which states that it has the high tensile strength.

Therefore, option (C) is correct.

Note: Next time you step in a room and switch on the bulb, know that it is tungsten which is playing a part in illuminating the room. Tungsten can also withstand high temperatures, so whenever you find high temperature, think tungsten and there is a good chance that it is present there.