We have,
Inner radius of tap = 0.75 cm
Length of water flowing in 1s = 7m = 700 cm
Volume of water per second derived from tap = πr‑2l
= 22/7 × 0.75 × 0.75 × 700
= 1237.5 cm3
∴ Volume of water derived in 1 hour (3600 sec) = (1237.5 × 3600)/1000
= 4455 litres