Fundamental Knowledge of Science Flashcards

Which physical principle is used by miners' self-rescuers (SCSRs) to generate breathable oxygen?

Answer: Chemical reaction of potassium superoxide (KO₂) with moisture and CO₂

SCSRs use potassium superoxide (KO₂) which reacts with exhaled moisture and CO₂ to release oxygen and absorb carbon dioxide.

Rock mechanics in mining defines 'stress' as:

Answer: Force per unit area acting on a rock mass

Stress (σ) = Force ÷ Area; it is an internal force per unit area within a rock mass, distinct from strain which is deformation.

Which wavelength range of electromagnetic radiation is classified as ultraviolet (UV)?

Answer: 10–400 nm

Ultraviolet radiation spans approximately 10–400 nm, shorter than visible light (400–700 nm) and relevant to arc welding hazards in mines.

What is the approximate percentage of oxygen in normal atmospheric air at the surface?

Answer: 21%

Normal atmospheric air contains approximately 20.9% (≈21%) oxygen, 78% nitrogen, and 1% argon and other gases.

In chemistry, which term describes a substance that donates protons (H⁺) in a chemical reaction?

Answer: Acid

According to the Brønsted-Lowry definition, an acid is a proton (H⁺) donor, relevant to understanding acid mine drainage chemistry.

The decibel (dB) scale for measuring sound is based on which mathematical relationship?

Answer: Logarithmic scale relative to a reference sound pressure

The decibel scale is logarithmic: dB = 20 × log₁₀(P/P₀), where P₀ is the reference sound pressure of 20 μPa.

Which property of water makes it an effective medium for fire suppression in underground mines?

Answer: High specific heat capacity and latent heat of vaporization absorbing large amounts of energy

Water's high specific heat (4.18 J/g·°C) and very high latent heat of vaporization (2,260 J/g) allow it to absorb enormous amounts of thermal energy when suppressing fires.