Questions & Answers

Question

Answers

A. \[{\text{9 litres}}\]

B. \[{\text{8 litres}}\]

C. \[{\text{7 litres}}\]

D. None of the above.

Answer
Verified

As per the given data,

Speed of water flow is \[{\text{30cm/s}}\].

Area of pipe is \[{\text{5c}}{{\text{m}}^{\text{2}}}\]

So, flow of volume of water per unit time will be \[{\text{30$\times$5= 150c}}{{\text{m}}^{\text{3}}}{\text{/s}}\]

As per the unit conversion \[{\text{1litre = 1000c}}{{\text{m}}^{\text{3}}}\]so,

Volume flow per unit time \[\dfrac{{{\text{150}}}}{{{\text{1000}}}}{\text{litre/s}}\]\[{\text{ = 0}}{\text{.15litre/s}}\]

And hence the water flows for \[{\text{1min = 60sec}}\]. So the total water that will pass the cross section is

\[{\text{ = 0}}{\text{.15}} \times 60{\text{ = 9litres}}\]

Hence, option (a) is our required answer.

Always write proper units and remember important conversions, as \[{\text{1litre = 1000c}}{{\text{m}}^{\text{3}}}\].