CMSP Fundamental Knowledge of Science 3 — Questions and Answers
Question 1: In the context of mine explosions, what is the Lower Explosive Limit (LEL) of methane in air?
- 1.5%
- 5% (Correct answer)
- 15%
- 25%
Correct answer: 5%
Methane's LEL is 5% by volume in air; below this concentration the mixture is too lean to ignite.
Question 2: Which type of radiation can be stopped by a sheet of paper and poses the least penetrating hazard in mining?
- Gamma radiation
- Alpha radiation (Correct answer)
- Beta radiation
- Neutron radiation
Correct answer: Alpha radiation
Alpha particles have very low penetrating power and are stopped by a sheet of paper or a few centimeters of air, though they are hazardous if inhaled.
Question 3: What chemical property makes hydrogen sulfide (H₂S) particularly insidious as a mine hazard?
- It has a distinct blue color making it easy to see
- High concentrations paralyze the olfactory nerve, removing the warning smell (Correct answer)
- It reacts violently with water to produce heat
- It dissolves in blood faster than oxygen
Correct answer: High concentrations paralyze the olfactory nerve, removing the warning smell
At high concentrations H₂S rapidly paralyzes the olfactory nerve so workers can no longer smell it, eliminating the natural warning of its rotten-egg odor.
Question 4: Which Newton's law is most directly applied when calculating the force required to move a loaded mine cart?
- Newton's First Law (inertia)
- Newton's Second Law (F = ma) (Correct answer)
- Newton's Third Law (action-reaction)
- Law of Universal Gravitation
Correct answer: Newton's Second Law (F = ma)
Newton's Second Law (F = ma) directly relates the net force needed to accelerate a mass, making it the basis for calculating haulage forces.
Question 5: When coal dust is suspended in mine air, it becomes explosive primarily because:
- Coal dust lowers the ignition temperature of methane
- Suspended particles dramatically increase the surface area available for rapid oxidation (Correct answer)
- Coal dust reacts with nitrogen to form flammable compounds
- Fine dust particles reflect heat, concentrating it at ignition points
Correct answer: Suspended particles dramatically increase the surface area available for rapid oxidation
Suspending dust creates an enormous surface area-to-mass ratio, allowing very rapid oxidation (combustion) when an ignition source is present.
Question 6: pH is defined as the negative logarithm of which ion concentration?
- Hydroxide ion (OH⁻) concentration
- Hydrogen ion (H⁺) concentration (Correct answer)
- Bicarbonate ion (HCO₃⁻) concentration
- Chloride ion (Cl⁻) concentration
Correct answer: Hydrogen ion (H⁺) concentration
pH = −log[H⁺]; lower pH means higher hydrogen ion concentration and stronger acidity.
Question 7: In electrical circuits used in mines, Ohm's Law states:
- Power equals current times resistance
- Voltage equals current multiplied by resistance (V = IR) (Correct answer)
- Current equals voltage multiplied by resistance
- Resistance equals voltage multiplied by current
Correct answer: Voltage equals current multiplied by resistance (V = IR)
Ohm's Law: V = IR, where voltage (V) equals current (I) in amperes times resistance (R) in ohms.
CMSP Fundamental Knowledge of Science 3
In the context of mine explosions, what is the Lower Explosive Limit (LEL) of methane in air?