The annual evaporation from a lake with surface area of 1500 hectare is 240 cm. What is daily average evaporation rate in hectare-metre per day during the year ?
- A9·863 Ha.mCorrect
- B3600 Ha.m
- C360 Ha.m
- D986·3 Ha.m
Solution
Concept
Volume of evaporation
Formula
Volume = area × depth
Step-by-step solution
1. Annual volume = 1500 ha × 2.4 m = 3600 ha·m. 2. Daily average = 3600 / 365 = 9.863 ha·m/day.
Explanation
Multiply the area by the depth to get the annual volume, then divide by the number of days in the year.
Why the other options are wrong
3600 ha·m is the annual volume, 360 and 986.3 ha·m are factors of 10 and 100 off.
Shortcut
1500 × 2.4 ÷ 365.
Common mistake
Forgetting to divide by 365.
Correct answer: A) 9·863 Ha.m