The explosive for blasting is usually expressed in terms of..................
💥 Understanding Blasting Calculations
Blasting for quarrying or construction is a precise engineering science. To break a specific amount of rock, engineers must calculate the exact quantity of explosive needed. Using too little will not break the rock properly, and using too much is wasteful, dangerous, and can damage the surrounding area.
Therefore, the question is asking for the standard unit used to measure the quantity of explosive material.
🔬 Detailed Analysis of the Options
C. Kilograms
This is the correct answer. Explosives are solid materials, and their quantity is measured by mass. Kilograms (kg) is the standard international unit for mass. When engineers design a blast, they specify the total mass of explosive required, for example, "150 kg of dynamite."
A. Explosive power
This is incorrect. Explosive power (also known as strength or performance) is a property of the explosive, not a unit of quantity. It describes how powerful the explosive is, often measured by its "Relative Bulk Strength" compared to a standard like TNT. You would choose an explosive based on its power, but you would measure its quantity in kilograms.
B. Volume of earthwork that can be blasted
This is incorrect. The volume of earthwork (measured in cubic meters) is the result you want to achieve. The amount of explosive needed is calculated based on this volume, but the explosive itself is not measured in cubic meters of rock. For example, you might need 0.5 kg of explosive to break 1 cubic meter of rock.
D. None of these
This is incorrect, as kilograms is the correct standard unit.
📊 Summary: Blasting Terminology
| Term | Description | Example Unit |
|---|---|---|
| Quantity | The amount of explosive material. | Kilograms (kg) |
| Property | The inherent strength of the explosive. | Relative Bulk Strength (RBS) |
| Result | The amount of rock to be broken. | Cubic Meters (m³) |
💡 Study Tips
- Think of Shopping: When you buy sugar, you ask for it in kilograms (quantity), not in "sweetness" (property) or "number of cups of tea you can make" (result). It's the same for explosives.
- Mass is the Measure: Explosives are physical substances. The fundamental way to measure a substance is by its mass.
- Power vs. Amount: Don't confuse the power of something with the amount of it you have. A small amount of a powerful explosive can do the same work as a large amount of a weak one, but in both cases, the "amount" is measured in kg.