MCQ Detailed View

Most gases do not conduct electricity under normal conditions because the neutral gas molecules do not have free charged particles. However, when a gas is subjected to very low pressure, its electrical conductivity increases significantly. This is because reducing the pressure decreases the density of gas molecules, allowing electrons and ions to travel more freely through the gas without frequent collisions.

At very low pressure, gases can become ionized when exposed to a high voltage, producing positive ions and free electrons. These charged particles act as carriers of electric current, enabling the gas to conduct electricity. This principle is applied in devices like neon lamps, fluorescent tubes, and vacuum tubes, where gases at low pressure allow electrical discharge and visible light emission.

In contrast, at normal pressure, the high density of molecules causes frequent collisions, which inhibits the movement of electrons and reduces conductivity. At very high pressure, molecules are even closer together, further limiting the motion of charged particles. Therefore, the most suitable condition for gas conductivity is at very low pressure, which facilitates the flow of electricity through ionized gas.

Understanding this concept is important in physics, electronics, and everyday science, as it explains phenomena such as glow discharges, plasma formation, and the working of gas-filled electrical devices. It also demonstrates the relationship between pressure, particle density, and electrical conductivity in gases.

The correct answer is Option 2 — Very low pressure, highlighting the condition under which gases can conduct electricity efficiently.