Water contained in a tank flows through an orifice of diameter 2 cm, under a constant pressure difference of 10cm of water column. The rate of flow of water through the orifice

Given, 

$\mathrm{Diameter}=2\mathrm{cm}\Rightarrow \mathrm{radius}=1\mathrm{cm}={10}^{-2}\mathrm{m}$

We know that,

$\mathrm{v}=\sqrt{2\mathrm{gh}}=\sqrt{2\times 9.8\times 10\times {10}^{-2}}=1.4\mathrm{m}/\mathrm{s}$

Now the rate of flow of liquid through orifice

$\mathrm{Q}=\mathrm{v}\times \mathrm{area}$

$\Rightarrow \mathrm{Q}=1.4\times 3.14\times {10}^{-4} =4.40\times {10}^{-4} =440\mathrm{cc}/\sec$

Hence the correct answer is 440 cc/sec.