Question

Water in a canal 1.5 m wide and 6 m deep is flowing with a speed of 10 km/hr. How much area will it irrigate in 30 minutes if 8 cm of standing water is desired

Answer 1

Speed of flowing of water from canal is 10km/h , means length of water flows in 1 hour = 10 km , so length of water flows in 30 minutes = 5km

Now, volume of water flowing from canal = length of water flows in 30 minutes × breadth of canal × deep of canal
= 5000m × 6m × 1.5m = 45000 m³

Let area of field = x m²
Then, volume of water irrigates into the field = area of field × height of water during irrigation
= x m² × 8× 10⁻² m = 0.08x m³

Now, volume of water flowing from canal = volume of water in field
45000 m³ = 0.08x m³
x = 562500 m²
We know, 1 hectare = 10000 m²
So, area of field in hectare = $\frac{562500}{10000}$ = 56.25 hectares