Question

Argon gas is used in electric bulbs.
A. True
B. False

Answer 1

The electric lamps glow at extremely high temperatures. Tungsten is a strong metal having a very high melting point and they are heat resistant as they do not burn readily at high temperatures, thus acting as insulators when used for any such purpose.

Complete step by step answer:
Electrical heating is used to produce light in bulbs. The filament inside the bulb must retain as much heat as possible on generating heat so that it can emit light and not melt at high temperatures.
For this, strong metal with a high melting point is used so that the filament should remain thermally protected and isolated as much as possible. Pure Tungsten is one such element used for making bulb filament as it has the highest melting point of 3695K. Also, its vapor pressure is very low and has great tensile strength out of all the metals used to conduct heat and electricity.
The glass chamber of the bulb cannot be filled with air because in presence of oxygen the metal Tungsten will be burned. Also, the glass cannot be vacuum otherwise the metal will evaporate at a high temperature. So only one solution to these problems is an inert gas. In the bulb chamber argon, an inert gas is used. an inert gas maintains the pressure inside the bulb and prevents the evaporation of metal.

So, the given statement is true. The answer is A.

Note:
One of the important reasons why tungsten is used in bulb filaments is that it is a metal and has a characteristic property of being drawn into wires, called ductility. This makes it very suitable for this purpose along with its resistance to withstand high temperatures. Although it has tremendous use, yet it has a limitation. Its hardness makes it more brittle and breakable. On smashing or hitting against anything hard, it might shatter or crack. The broken tungsten cannot be repaired further. Also, it is heavy metal.