Consider a cylindrical tank of radius $1 \mathrm{m}$ is filled with water. The top surface of water is at $15 \mathrm{m}$ from the bottom of the cylinder. There is a hole on the wall of cylinder at a height of $5 \mathrm{m}$ from the bottom. A force of $5\times {10}^5 \mathrm{N}$ is applied an the top surface of water using a piston. The speed of efflux from the hole will be :
(given atmospheric pressure $P_A=1.01\times {10}^5 Pa$, density of water ${\rho }_w=1000 \mathrm{kg} {\mathrm{m}}^{-3}$ and gravitational acceleration $g=10 \mathrm{m} {\mathrm{s}}^{-2}$)

• A

  $11.6 \mathrm{m} {\mathrm{s}}^{-1}$
• B

  $10.8 \mathrm{m} {\mathrm{s}}^{-1}$
• Correct answer
  C

  $17.8 \mathrm{m} {\mathrm{s}}^{-1}$
• D

  $14.4 \mathrm{m} {\mathrm{s}}^{-1}$

Hence, the correct answer is option: 'C'.