Q. A unit of area, often used in measuring land areas, is the hectare defined as $10^{4}$ $m^{2}$. An open-pit coal mine consumes 75 hectares of land, down to a depth of 26m, each year. What volume of earth, in cubic kilometre, is removed in this time?
A) 0.01
B) 0.02
C) 0.03
D) 0.04
Explanation
Required volume $= \frac{75 \times 10^{4} \times 26}{10^{3} \times 10^{3} \times 10^{3}}(km)^{3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.