Density from energy densities

Steps:

• Volumetric energy density = specific energy × density, so density = (34.9 MJ/L) / (41.5 MJ/kg) = 0.841 kg/L.
• Convert kg/L to kg/m³ by multiplying by 1000: 0.841 × 1000 = 841 kg/m³.
• Express as scientific notation: 841 = 8.41 × 10² kg/m³ (article values yield ≈8.35 × 10² kg/m³).
• Match to option A.

Why A is correct:

• It equals the density calculated from the formula for energy density (volumetric = mass-specific × ρ).

Why the others are wrong:

• B: Gives a volume (m³), not density (kg/m³).
• C: Incomplete scientific notation, invalid units or value.
• D: Far too low (12 kg/m³) for liquid fuel density.

Final answer: A