Explanation

• Fluorescent lamps mainly use argon gas (often with a small amount of mercury vapor).
• Electric current excites the gas and produces ultraviolet (UV) light.
• The UV light then hits the phosphor coating inside the tube.
• This coating produces visible light.
• Argon helps in starting and maintaining the discharge.

Last verified on 14-06-2026

Explanation

• The usual gases used for lifting airships are hydrogen and helium.
• Hydrogen is the lightest known gas and thus has great lifting capacity,
• Helium is not as buoyant but is far safer than hydrogen because it does not burn.

Last verified on 01-04-2026

Explanation

• Natural gas burns with a clean blue flame.
• It indicates complete combustion.
• Blue flame produces more heat and less smoke.
• It is efficient and less polluting.
• Natural gas mainly contains methane (CH₄).

Last verified on 24-05-2026

Explanation

• Effusion is the escape of gas molecules through a tiny hole.
• According to Graham’s law, rate of effusion ∝ 1/√molar mass.
• Lighter gases effuse faster than heavier gases.
• Among given options, hydrogen has the lowest molar mass (H₂ = 2 g/mol).
• Therefore, it moves and escapes the fastest.

Last verified on 19-05-2026

Explanation

• Ozone (O₃) is both beneficial and harmful depending on its location.
• In the Ozone Layer, it protects life by blocking UV rays.
• At ground level, it becomes a pollutant harmful to lungs and plants.
• Thus, it has a dual role in Earth’s atmosphere.

Last verified on 02-05-2026

Explanation

Composition of Air:

• Nitrogen → 78%
• Oxygen → 20.95%
• Argon → 0.93%
• Carbon dioxide → 0.04%
• Other gases → very small traces

Last verified on 30-04-2026

Explanation

• Sugar is the most soluble chemical in water.
• Sugar is made from sucrose.
• Sugar dissolves readily in water due to its polar nature.
• It forms hydrogen bonds with water molecules, increasing solubility.
• Used widely in food and beverages due to easy dissolution.

Last verified on 23-04-2026

Explanation

• Energy due to motion is called kinetic energy.
• Any moving object possesses this energy.
• It depends on mass and velocity of the body.
• Faster motion means more kinetic energy.

Last verified on 11-04-2026

Explanation

• Glass and pitch are examples of pseudo solids.
• Pseudo solid is a solid which possesses the property of liquids.
• Glass is a pseudo solid and in a very slow process, it flows like a liquid due to which the base of glass gets thicker than top.

Last verified on 02-04-2026

Explanation

• Nitrogen (N₂) makes up about 78% of Earth's atmosphere.
• It is a colorless, odorless, and inert gas, essential for life but not directly used in respiration.
  

Additional information:

Composition of Air – Approximate %:

• Nitrogen – 78%
• Oxygen – 21%
• Argon – 0.93%
• Carbon Dioxide – 0.04%
• Other trace gases (Neon, Helium, Methane, Krypton, etc.) – 0.03%

Last verified on 18-03-2026