Easy MCQ +4 / -1 PYQ · JEE Mains 2021

The pressure acting on a submarine is 3 $\times$ 105 Pa at a certain depth. If the depth is doubled, the percentage increase in the pressure acting on the submarine would be :

(Assume that atmospheric pressure is 1 $\times$ 105 Pa density of water is 103 kg m$-$3, g = 10 ms$-$2)

  1. A ${{200} \over 5}$%
  2. B ${{200} \over 3}$% Correct answer
  3. C ${{3} \over 200}$%
  4. D ${{5} \over 200}$%

Solution

P = P<sub>0</sub> + h$\rho$g = 3 $\times$ 10<sup>5</sup> Pa<br><br>$\Rightarrow$ h$\rho$g = 3 $\times$ 10<sup>5</sup> $-$ 1 $\times$ 10<sup>5</sup><br><br>$\Rightarrow$ h$\rho$g = 2 $\times$ 10<sup>5</sup><br><br>$\therefore$ 2h$\rho$g = 4 $\times$ 10<sup>5</sup><br><br>$\therefore$ P' = P<sub>0</sub> + 4 $\times$ 10<sup>5</sup><br><br>$\therefore$ P' = 5 $\times$ 10<sup>5</sup> Pa<br><br>$\therefore$ % increase in pressure = ${{P' - P} \over P} \times 100$<br><br>$= {{(5 - 3) \times {{10}^5}} \over {3 \times {{10}^5}}} \times 100$<br><br>$= {{200} \over 3}$%

About this question

Subject: Physics · Chapter: Properties of Solids and Liquids · Topic: Elasticity

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