Explanation

• Hydrogen and helium are the two lightest gases.
• Helium is the second most abundant element in the universe, after hydrogen.
• Helium has monatomic molecules.
• It is the lightest of all gases except hydrogen.
• Hydrogen is the lightest gas known.
• It provides the maximum lift for balloons due to its very low density.

Last updated question 17-02-2026

Explanation

• Mercury Symbol: Hg
• Atomic number: 80
• Melting point: -38.83 °C
• Atomic mass: 200.59 u

Last verified on 13-03-2026

Explanation

• The unit of pressure is N/m² (Newton per square meter).
• It is also called Pascal (Pa).
• Pressure means force applied per unit area.
• Higher force or smaller area increases pressure.

Last verified on 17-06-2026

Explanation

• Marconi invented Radio.
• Radio was invented in 1895.
• Guglielmo Marconi was an Italian inventor.

Last verified on 12-08-2026

Explanation

• A series of steps is called a staircase, stairway, or a flight of stairs

Additional information:

• Tread: The flat, horizontal top surface where you place your foot.
• Riser: The vertical part that forms the gap between one step and the next.
• Nosing: The front, rounded edge of the tread that sticks out over the riser

Last updated 14 August 2026 by NA

Explanation

• Cast iron pipes are strong and durable.
• They are mainly used for underground water-supply lines.
• They can withstand high water pressure.
• They have a long service life.
• They are suitable for large and permanent water-supply systems

Explanation

• Plain Sedimentation (4–8 hours): Relies purely on gravity for natural particle settling.
• Coagulation-Sedimentation (2–4 hours): Uses chemical coagulants to accelerate particle clumping and settling.
• Detention Time Formula: Calculated as (T =V/Q), dividing tank volume (V) by flow rate (Q) [KETOS].

Explanation

• Montague fall is a type of canal fall.
• It uses a parabolic glacis for energy dissipation.
• The parabolic shape helps control high-velocity flow.
• It converts excess energy and reduces scouring.
• It is used in irrigation canal systems.

Explanation

A fluid flow in which the velocity vector has the same magnitude and direction at every point at any given instant is known as a uniform flow.

Explanation

• Traditional walking sticks are commonly made of wood.
• Wood is strong and durable.

Last updated 13 August 2026 by NA