18 October 2026: pressure, mixtures, economics and heritage quiz

3,000 N per square metre — Pressure = force / area = 90 / 0.03 = 3,000 N per square metre.

One-third of the original — At fixed force, pressure varies inversely with area, so tripling area divides pressure by three.

Filtration — A suitable filter retains insoluble sand while water passes through.

Different particle sizes — Sieving separates particles according to whether they pass through a chosen mesh.

Three chairs — The change gains one table and forgoes three chairs; the stated trade-off is three chairs per extra table.

A point strictly inside the frontier — A point strictly inside the production possibility frontier represents output below the model’s available capacity.

Mesosphere — The order begins troposphere, stratosphere, mesosphere, thermosphere and exosphere.

Nitrogen — constituent; stratosphere — layer — Nitrogen is a gas in air; the stratosphere is one of the atmosphere’s vertical layers.

Patan — Gujarat — UNESCO identifies Rani-ki-Vav at Patan in Gujarat.

Subterranean stepwell — UNESCO describes a stepwell combining stepped access, water architecture and sculptural design.