From a tap of inner radius 0.75 cm, water flows at the rate of 7 m per second.

Radius of the water tap $=0.75 \mathrm{~cm}=0.0075 \mathrm{~m}$

Length of the water flowing in $1 \mathrm{~s}=7 \mathrm{~m}=700 \mathrm{~cm}$

Volume of water flowing in $1 \mathrm{~s}=\pi(0.0075)^{2} \times 700$

Volume of the water flowing in 1 hour $=\pi(0.0075)^{2} \times 700 \times 60 \times 60$

Volume of the water flowing in 1 hour $=\frac{22}{7} \times(0.0075)^{2} \times 7 \times 60 \times 60=4.455 \mathrm{~m}^{3}=4455 \mathrm{l}$

$\left(1000 \mathrm{l}=1 \mathrm{~m}^{3}\right)$