Question

What is the pressure 200 m below the surface of the ocean if the sp. gravity of sea water is 1.03 : [Atmospheric pressure$=1.013\times {10}^{5}N/m^2$].

• A. $21.2\times {10}^{5}N/m^2$
• B. $20.4\times {10}^{5}N/m^2$
• C. $40\times {10}^{4}N/m^2$
• D. $21.2\times {10}^{6}N/m^2$

Answer 1

The correct option is A $21.2\times {10}^{5}N/m^2$

The gauge pressure at any depth is given by,

$P_g=\rho gh$

Given, the atmospheric pressure to be $P_o=1.013\times {10}^{5}Pa$

The pressure at this depth will be,

$P=P_o+P_g$

= $1.013\times {10}^5+1.03\times {10}^3\times 10\times 200$

= $21.2\times {10}^{5}Pa$