Permanent hardness of water is caused by: MCQ with Answer and Explanation

Explanation:
Calorific value is determined using a bomb calorimeter, where a known mass of fuel is burnt in excess oxygen in a sealed bomb, and the heat released is absorbed by a known mass of water. Temperature rise is measured. Corrections for cooling, wire, and acid formation are applied. Units: kJ/kg or kJ/mol. The bomb calorimeter works at constant volume.

Explanation:
Distillation separates a mixture of two or more miscible liquids with different boiling points. The liquid with the lower boiling point vaporizes first, is condensed, and collected separately. Fractional distillation is used when the boiling point difference is less than 25 K. Simple distillation works for larger differences. Filtration separates solids from liquids; sublimation separates sublimable solids; chromatography separates dissolved substances based on differential adsorption.

Explanation:
Radioactive decay emits alpha, beta, and gamma rays. Alpha particles are heavy and positively charged, stopped by paper. Beta particles are lighter, stopped by aluminum. Gamma rays are high-energy electromagnetic photons with no mass or charge, giving them the highest penetrating power; they require thick lead or concrete to be significantly attenuated.